Transcript: End-of-Season Health & Safety Briefing, Feb. 7, 2022

The NFL hosted a media briefing on February 7, 2022, to share 2021 regular season injury data and provide updates on COVID-19 mitigation ahead of Super Bowl LVI.


  • Dr. Allen Sills, NFL Chief Medical Officer
  • Jeff Miller, NFL Executive Vice President Overseeing Player Health & Safety
  • Dr. Christina Mack, Vice President of Epidemiology and Clinical Evidence and Head of Surveillance and Agile Analytics at IQVIA and advisor to the NFL

Miller: Afternoon everybody. It is good to see you all and good to do this via Zoom—that's different. A couple of top-line points and then I'll shoot it over to Allen and Christina and we'll all have a conversation around the topics.

As a starter, you know making it through season two of the pandemic is a success. We're obviously quite thrilled and very grateful to be able to work our way through this year, as it presented a set of different challenges. As we like to say, applying 2020 solutions to 2021 problems wouldn't have been the right way to go about this and so we had to be, as usual, relatively flexible and adjust as we moved and that required a lot of collaboration with the players, Players Association and a lot of experts certainly on our side under Allen's leadership to get that done. So, he'll talk to you a little bit about that at the outset, and I'm sure Christina will chime in too about how we made the decisions that we made about COVID throughout the course of the season. All data-driven, all in consultation with experts, including public health officials, to get us to a good place and, knocking on wood, to get us to a good place at the end of this week. So, we're very grateful for all of that.

Importantly, as you know, there were minor disruptions throughout the course of the season—only three games moved and even that was very modestly. So that was I think that was a success in many ways as well. A big theme that we'll talk a little bit about, of course, was the change in the season structure – going from 16 and 4 for many years previous to 17 and 3, what we thought about that from an injury perspective, and what we saw. So, we've talked to you in previous years about why it is we were comfortable making that change, so we'll go into that a bit.

Lastly, we'll talk about some individual injury areas. We always talk about concussion. We will touch on that, some lower extremity injuries, and then certain things that we're going to focus on between now, the combine, the March owners meeting and the May owners' meeting when rules are adopted and some of the primary areas of focus there. So, we'll talk about things that jumped out in the data for us both this year and in previous years, and we'll talk about what our thinking is around that.

And then of course, I am happy to answer any questions on those topics or anything related to health and safety as it comes up. So, that's sort of the general topline. Allen, do you want to dig in on Covid for everybody? We will start with that major topic area.

Sills: Sure! Happy to do that Jeff. Good afternoon, everybody! It is great to actually see many of you, and I look forward to seeing some of you in person later this weekend in LA. I will talk a little bit about COVID and in thinking about the entirety of the season, and the first thing that jumps out at me as a physician is the ability to get through the season in what I would consider a safe manner. By that, I mean focusing on that we did not see significant serious illness, hospitalizations or death. We had one hospitalization throughout the entire season, and that was for one night only. That was one case out of our over 7,000 players, coaches and staff. So, I think that's an important point because that's the goal, ultimately, of all of our protocols—keeping everyone safe. I think that's the thing we used as a benchmark. And I think that the ability to get through the season and avoid serious illness ties into our high vaccination rate as we will talk about.

As you've many of you've heard me say, I sort of almost divide the season into two halves: there's the pre-Omicron and the post-Omicron, because the experiences were very different. You know, our set of protocols and what we had in place. For example, we averaged about 28 cases per week – positive cases – in the first five months of the season. Then Omicron hit us about December 12th, and I've described it, as others have, like a tidal wave. It just came in and it washed over everyone. It affected everyone and we saw our case rates go up as much as tenfold in the course of a week.

So, that really caused us to need to pivot and change our strategy. I think that once again, we saw in that tidal wave that the NFL was a bit of an indicator for where we were going—the wave if you will, hit us and we detected it first in the NFL because of our ability to test, because of our careful monitoring and screening, and our protocols.

What omicron has done is allowed us to gather a lot of data that we have, again, shared with public health officials including the CDC. Through the course of the season, we ended up making nine different protocol changes. We did 945 contact traces, and we identified more than 4,000 high-risk close contacts. So, an enormous amount of effort went into administering those protocols, but the data that we've taken from that – we've shared broadly with the public health community including the CDC. We've had a lot of communication with the CDC during this Omicron period and they've been to review our data and, I think, take some important learnings from it.

Importantly, from my standpoint, I think that Omicron appears to have peaked and definitely is on the way down in our population. Once again, that's not only good news for the NFL, but I think it's good news for the country as a whole because we have tended to be an indicator of where things will follow in the country after a few weeks.

I mentioned earlier that I think vaccinations were an important thing for us, and as you know we were virtually 100% vaccinated with our staff and about 95% with our players. That is an important achievement, and I think that there was a lot of effort that went into that. There was a lot of education that went into that. Education in many different formats: formal presentations, webinars, Zoom calls and one on one discussions. That was done by the league, the Players Association, the club medical staffs, coaches, trusted advisors and many, many different people. I think it's a great reflection of the teamwork and this holistic approach that everyone had.

I think there's no question that there were some incentives for being vaccinated beyond the obvious ones for health. I think that was an important part of the program because when we started, a lot of players were not vaccinated at the start of training camp, and most chose to become vaccinated during training camp and through the ensuing season. So, I'm proud of that effort to get to that vaccination rate, and as I've said before, I think the pandemic in our country would have looked differently had the country been at that type of rate.

And I can tell you that we clearly saw beneficial effects from the vaccine. If you look throughout the course of the season; again, starting back in July, we consistently saw higher rates of COVID in the unvaccinated – higher positive test rates – than we did in vaccinated individuals, and that ranged from twice as many to seven times as many. There's some fluctuation during the season because the pool of people is going down as many of those who are unvaccinated contracted COVID, but the point is: we saw higher rates of disease in the unvaccinated at all time points. I think that's an important takeaway from our experience this season.

One other thing that we did is: we did do a study of antibodies, and maybe I will turn to Dr. Mack to talk a little bit about why we did that study and what we're seeing preliminarily in that data. Christina?

Mack: As Allen noted, as we embarked on the season it's an exercise in public health and following the science but also a matter of gathering the data so that we know how to pivot and evolve. After we have everyone vaccinated, we need to understand the incidence, and as Allen said, we continued to see a higher incidence of COVID among unvaccinated individuals.

It was also important for us to understand immunity over time as this very highly vaccinated population got farther from that initial vaccine. To that end, the NFL offered antibody testing and launched an antibody study to the population, largely focused on tier one and tier two staff. The goal of that study, as we did have this very highly vaccinated population, was to understand, as they walked farther in time from that first shot, what did their antibodies look like over four months, five months, six months?

What we saw in that population was that those immunities waned over time for the majority of the individuals as they got farther away from that first vaccination. That showed us the need for boosting, and so when we did mandate, or require, boosting for staff and highly encourage it for the entire population including players, what we saw, as we looked more into the antibody study and took that second draw three months later, was that when individuals are boosted, their antibody titers, which have gone down in some cases considerably, went back up to that highest level. Importantly from that, when we looked at COVID incidence among the individuals we had antibody results for, we did see higher rates of COVID among those with those lowest titer levels that hadn't yet been boosted. So again, kind of taken together, from a public health perspective, it was really important to use the results from that study to require and also encourage booster shots. We saw the benefits of that in the population, as Dr. Sills said. Even though we had cases along with the rest of society and the communities, we saw very few extremely sick people and hospitalizations, so we will continue to assess that as we move forward.

Sills:I will just point out, Christina, that antibody study is ongoing. We have got a lot of people who are just getting their second draw right now, so we'll have more to say, and we'll have more data and more results in a few weeks and months' time, as we continue to look at that and what it means, particularly in the era of these new variants.

Let me close this section by just talking a little bit about symptom screening and targeted testing, as we've called it, and also the five-day return. I mentioned before that we almost had two different eras between the pre-Omicron and then the Omicron era. The Omicron era, being a sort of new phase of the pandemic, really called for a new strategy. One of those strategy adjustments that you all know that we made was around targeted testing. I mentioned that Omicron hit us around December the 12th. December 16th is when we changed our testing paradigm from what we would call surveillance testing – randomly surveying people at time intervals – to a much more targeted testing. This really mimicked what we've been doing in healthcare and what we were doing in healthcare at the time. As doctors and nurses at our health care facilities, we've seen this, of course, in other countries around the world as well.

What we did is, we said, we want to be focusing our testing on the most likely group to be contracting COVID, and that's those with symptoms. So, we really doubled down on emphasizing symptom screening and checking every person, in person, every day, asking them for symptoms, and testing anyone who offered any symptoms – as opposed to just randomly surveying at certain time points.

I think that was a success. If you look at it, for example, in the last week of the regular season, we still did over 4,000 tests—over 4,200 tests in the last week of the regular season. We saw, once we adopted that targeted testing, as I mentioned, on December 16th, our case numbers actually increased for the next two weeks' time. So, we saw going from one era of testing, a step up, and then another step up before we saw that wave start to crest and come down.

Even though we switched to this testing strategy of targeted testing, we were detecting the people that we wanted to detect, which were sick people. And so we feel confident that we were not missing outbreaks and there are a couple of reasons beyond that. We're not finding symptomatic people on our symptom screening, and I think that is reflective of the fact that the case numbers have just started to drop off. That's the same experience that people had with Omicron throughout the world—it came in like a tidal wave, having a big effect on a number of people, and then it fell off rather quickly. Again, that's what we saw in the NFL.

As an interesting observation, when clubs got eliminated from the playoffs, obviously they continued to test for the few days following that. As many of you know, there are exit physicals that are done, there are exit meetings and other things, and we did not see positive cases coming in on those teams that were eliminated. Meaning that there weren't people who said, "yeah I've actually had symptoms for a few days, but I didn't say anything about it because we're in the playoffs and now that we're eliminated, I'm going to admit to it." We didn't see that occur at all, which I think, again, reinforces our belief that we were detecting people with the symptoms screening.

And so we don't think that we missed undiagnosed cases, as we've not seen any outbreaks among teams that were involved in the playoffs or obvious spread. Again, we couldn't really make that observation in the early weeks of the Omicron wave because there were just so many cases, but as the case numbers have dropped off, we're not seeing, among those teams in the playoffs, anything more than usually low single-digit numbers in those teams in this era where the cases have fallen off.

So, the other piece of that that we changed, as you all know, is the five-day return. We made that change, I believe, on December 28th, where we followed the CDC's guidance suggesting that you could come back after five days. Again, we've tracked that very carefully, and I would emphasize a couple of points. One is that it wasn't just an automatic return of five days; anyone who was affected had to be cleared by the team physician, and then when they came back, they were continually monitored for symptoms, and they were wearing a mask inside at all times. I can tell you that within that group of people who came back after five days, we did not see anyone develop recurrent illness as they came back nor have we seen what we would consider to be forward transmission from those individuals when they returned. Again, this is after that protocol change that we made at the end of December as the case numbers started to go down to a level where we could sort of detect signal.

I think the take-home messages here are that we feel like this targeted testing was effective as a screening tool, particularly during this Omicron era. And that feel like the five-day return has been able to be done safely within the parameters of our protocol. I think this has implications for other sports at other levels, but also society. You can keep people safe if you test them for cause, and that symptom-based testing really works, particularly when you have results that are rapidly available. We think the PCR test remains the gold standard and that the test that you use actually matters. And we've used PCR testing because we think it is the gold standard, but, again, with the five-day return, clearance by a physician, and masking, we did not see substantial transmission. I think, again that our high-risk close contact assessment and action on that has also been a positive part of our experience this year. So, let me stop there. Jeff, I'll kick it back to you to talk season structure.

Miller: So, let's talk season structure, and then I'll move from there into some of the injuries. Just as background, as you recall, we did an analysis when we were talking about moving from 16 and 4 to 17 and 3 to look at the impact it may have on injuries. By removing one preseason game and replacing it with a regular-season game, as well as the practices and other activities within that, we made a prediction that there would not be a difference as it related to injury rate — 'statistically insignificant' is the term that we use.

And that proved to be true. As we recall, preseason games have the highest injury rate of any activity that players engage in. Regular season games are lower, and as we looked over the course of the season, as we moved to 17 and 3, we did not see a difference. The other item that we wanted to examine, as part of that calculation, was whether that 18th week – 17th  game of the regular season – would see a substantial uptick in injury rates as a result of fatigue or whatever the case may be as the regular season grew by a game. We didn't see it. Certainly, the injury rate in the last week of the regular season, week 18, was no higher than in previous weeks. In fact, it seemed to be a bit of a drop-off—not sure that that's statically significant or not. I think we have a chart on that to show you the numbers.

The yellow line there is 2021 and the other lines represent the averages from 2015 to 19. The sort of anomalous year of 2020, which is not a great comparison for a lot of reasons. But that's where we ended up for this year -- a small decrease in week 18. Again, I don't think it's statistically significant that it decreased in week 18, but probably fair to say just didn't go up at all.

And so from a fatigue perspective, or any other causative reasons to be concerned about the last week of the regular season, we didn't see it, and overall, we didn't see any difference as we move season structure, at least this year, from 16 and 4 to 17 and 3.

Moving on to some specific injury areas, let me start with concussions, something we update everybody on every year. A notable year this year; this is the fewest number of concussions we've seen since we've really been tracking this going back to 2015. And that's regardless of the time frame you take a look at. So, overall, preseason, regular season, practices and games, the all-in sort of number – we were down the lowest that we've seen, consistent with the number over the last couple of years of dropping off about 25%. We continue to be around there if not more so. We saw fewer regular-season game concussions this year, despite playing 17 games, than we've seen in the previous year, despite playing 16 in those.

So, again, a good year, not just on the raw numbers of concussions, but the rate of concussions going down. In preseason games, we saw the fewest number of concussions in preseason games, and you'll say: "well, of course, you only played three." Yes, that part is true, but on a rate basis, we also saw the lowest number of concussions in preseason games. So, all of these are good news stories overall. What we can attribute those to – that's obviously something we're going to spend a lot of time on – the causes of those injuries, whether they were helmet-to-helmet contact, helmet-to-ground, what position suffered more injuries, what play types – all the many things that we study between now  / Super Bowl and Combine into the discussion with the Competition Committee – are areas where we're going to go deeper and more exacting.

One thing that does jump out from the data, despite the fact that it was a good overall year, is that we're looking at about one out of six concussions in the regular season occur on special teams. So, between the punt and the kickoff, there's a disproportionate number of concussions that are occurring on only a couple of plays, which, obviously, are not played as often as plays from scrimmage.

So that's something that's going to be a primary area focus for us on the health and safety side, and in conjunction with our friends in football. We'll take a look again at kickoff, take a look again at punts, and the injury rates on those plays. Allen will talk about that in a little bit as well, as relates to other injury types. But on concussions, that jumps out of the numbers, for what is otherwise a very good story, that number pulls itself out.

Again, a very good year as far concussion numbers go. There always will be more work to do, but they're the lowest that we've recorded to this point, and we've identified at least one area related to the game where we want to spend a great deal of time.

Couple other things we'll take a look at and need to dig into are, again, offensive linemen – especially during preseason practices, where we see a lot of concussions relative to other positions, we want to drive those numbers down as well. And I'm sure that as we look at the data and the video, more will jump out at us.

Now, concussions aren't the only thing we're going to be taking a look at as it relates to head injuries. This is something that I'm going to defer to a neurosurgeon about in a minute. But a lot of the innovation work that we do to be able to identify injuries on-field, as a result of our partnership with AWS, artificial intelligence and machine learning has enabled us to generate some new tools. And to actually begin to identify head impacts, as opposed to simply diagnose concussions, which is something that we think is very important and is going to help us advance the health and safety of the sport as it relates to head injuries.

So Allen, if you want to take a minute on that, that might be useful.

Sills: Before I do that, I might put up slide two, just to give everybody a visual on the concussions here. This is the total number, as Jeff said, you can see in 2021 we actually had the lowest total in regular season games, even though we added an extra game. Again, we have been in this range for about four years now, a substantial drop from where we were back in 2017. The point is that that 126 number is not only the lowest absolute number, but it's with an additional game. As Jeff mentioned the preseason rate of concussions per game and regular season rate was identical which again, we think is an important advance going forward.

Switching over to talk for a moment about head contact. I think this is a really important message. We've obviously had some success about concussions as you have seen, but we don't think that is the full story. We want to make it a priority to eliminate avoidable head contact from the game. That's a strong statement, but what I mean by that is: there is always going to be some unavoidable head contact; players hit the ground with their heads, inadvertent collisions, but to the extent possible, we believe that eliminating avoidable head contact is an appropriate goal.

Part of that goal is to be able to measure those contacts, and that is where we've made tremendous progress in trying to take the head out of the game. We now have the ability to measure contact through instrumented mouthguards, I think most of you are familiar with that program. And, very excitingly, now, through our partnership with AWS, and using artificial intelligence, we can actually assess numbers of head impacts by video and that saves hours and hours of what is a very laborious process.

What that does is that now gives us an ability to quantify how much head contact is occurring. Totals for a team, totals for a player and to determine where and how that's occurring. So, we think that to achieve this goal of eliminating avoidable head contact, we're going to need that data so that we can teach better techniques, we can think about how we train and how we practice, we can look at what rule changes might be appropriate and really look beyond the helmets in how we achieve this. We think that the use of the Guardian Cap is also going to be important, many of you heard us talk about that before. That's a helmet add-on that reduces the volume of contact or, reduces rather the intensity of the blow when players are wearing that.

We'll have a lot more to say about that, there's a lot of work to be done but we now have tools to quantify these head impacts and we believe as a stated goal that we want to, as I said, eliminate avoidable head contact.

I'll switch gears to talk a little bit about special teams for a moment. Jeff referenced this before, I think this is the other big, what I would say call to action, and that is that we feel that special teams has a disproportionate injury rate at the present time. For example, let me give you some statistics: one in every five injuries of all types in the league occurs on special teams. One out of five. Jeff mentioned that one out of six concussions occur on special teams plays, and we saw this year 30% of all ACL injuries occurring on special teams, and 29% of all lower extremity strains.

Simply put, these special teams plays have a disproportionate rate of injury, compared to how frequently the play occurs. We think that's something that demands our attention. That's going to, again, involve looking at all the components of not only the play itself, but who's playing, how they're trained, how that play is practiced, and coming up again with a comprehensive strategy around reducing these injuries. Again, there's a lot of lower extremity strains on the special teams plays, a lot of these ACL injuries and certainly the concussions.

And the punt play, I think, is particularly the one that would be targeted by us. If we could go to slide number four, I think you'll all see on this slide, we're going to show you a slide that has a rate. This is an injury rate by play type. And the red line is the punt play. I think the data really speaks for itself. Again, you can see the rate of injury on the punt play far exceeds the rate on run, pass, and even kickoff plays, and certainly field goals and extra points are lower. As Jeff would tell me, you don't have to be a brain surgeon to see that this jumps out and needs attention because of that injury rate that we're seeing on that particular play.

Diving into that in a little bit more detail, lower extremity strains were up last year overall.

Miller: Can I just jump in one quick second? I just want to make a quick point, because Allen said this, but I think it's worth underlining. Whatever we choose to do in this space, you know, it may be related to the rules, or it may not be. I don't want to mislead the group. It may be training, or how players are trained around special teams. You know, running at full speed and getting jostled along the way is not a commonplace occurrence for a lot of players. Taking a look at the rosters and players moving up and down from practice squads to the rosters and potentially playing special teams. The frequency with which a player who is on special teams participates in a game, right, it is frequently non-starters who are on special teams. All of those sorts of things are areas where we need to look at. I know a lot of people's heads will go to, you know, rule change is necessary. That may be, and that's something that we'll investigate, but there's a lot of potential interventions now that we will take a look at as we study this issue.

Sills: Yeah, great point. Let me dive into, just quickly, a couple of points on lower extremity injuries. Our strains were up overall, and that's lower extremities strains, which means hamstrings, quadricep strains, calf strains, and abductor strains. There's really, it's a timing issue. We can put up the slide about that.

You can see here that we have one peak that's occurring over in what I call the acclimation period, when we first get together and start the ramp up. And then you see a big spike here on day eight or nine in training camp, that sort of corresponds to what we would say is the contact integration period, when we're putting pads on and starting to get after it.

I think that we feel that this is really related to the structure of those two periods of time. This is continuing to be a problem because, not only do these injuries lead to a lot of lost time, but many of them become recurrent during the course of the season. We've got some data-backed observations that we want to share with coaches, not only head coaches, but coordinators and other coaches. We'll be doing that in the upcoming meetings and combine. We certainly will share this result with our medical staff and the players as well. We think ultimately we're just going to need to do these ramp ups in a smarter and more data driven way. This will be a real point of emphasis in research for us going forward as well.

We talked about two other groups of injuries, one being the knee injuries, the ligament injuries, ACL, MCL, and so forth. We've mentioned that there's a disproportionate number on special teams plays. So we've got, again, a very comprehensive effort underway to look at that. This year, we tracked the cleats that were worn by every player, and we're looking at relative injury rates per cleat. We're also doing an engineering analysis of different surfaces, all of the different turf systems, as well as natural grass systems to look at their performance and calculate injury rates. We'll be analyzing all that and putting together injury reduction strategies as we try to understand what's driving these injuries and ways that we can reduce these going forward.

I would also call out, as far as the hamstring, again, that is the most common injury suffered by an NFL player. If you look at just raw numbers – it's the hamstring injury. 75% of players will ultimately miss time as a result of that injury. A lot of them, again, on special teams plays as we mentioned before, 40% to 45% over the last two years of our game hamstring injuries have happened on special teams plays. I think most of you are familiar that one thing we did this year is we awarded four million dollars through our scientific advisory board to researchers at the University of Wisconsin, specifically around this idea of prevention and treatment of hamstring injury. So it is something that we've got more work to do on, but that we're excited about attacking as well. Christina, let me ask you, is there anything you want to add to the body of work we just talked about there.

Mack: Sure, on this topic of hamstring strains, I think the other really important piece for comprehensive injury reduction is that they are very likely to recur – both hamstring and other strains. And so all of these efforts that Dr. Sills just described, they're occurring as players come back to the season, where we're preventing those first strains, we're going to prevent not only those, but future injury, because they have up to 20% recurrence throughout the rest of the season. It's kind of a multiplied gain to prevent those early on.

Sills: Jeff, we'll toss it back to you to talk on the pain management as we wrap up here.

Miller: Yeah, sure. Last topic then happy to take some questions. I'm sure many of you saw last week, we announced through our Pain Management Committee, which is a collaborative effort with the Players Association, a desire to do more research into understanding alternative means of pain management for our player population and hopefully for benefits beyond the NFL certainly. We made two grants: one to the University of California, San Diego and another one to a university in Canada to study cannabinoids. We put out a request for proposals on alternative pain approaches. Certainly, there were a lot around cannabinoids, but other things as well, and an independent group chose these two grants, for a total of about a million dollars, to take a look at cannabinoids as a potential alternative to current pain use.

Some of the experts on the committee that said there's just not enough research into these spaces. There are a lot of claims, but not a lot of proof. So we're happy to do our part to pursue that. Both of those research projects are going to take about three years and we're hopeful to get some better understanding of the research in this space. And if the Pain Management Committee wants to pursue further research, or we understand some things that we need to take a look at, we'll do more there as we continue to look for ways to improve the health and safety of our sport for the players who play it.

We're happy to take questions.

QUESTION: Dr. Sills, is there any way that you see – any way theoretically possible that a player or players would test positive this week and have to miss the Super Bowl, or do you think it's highly unlikely?

Sills: I think it's absolutely possible, because if they have symptoms and we test them and they're positive, then obviously they would miss the game. We're continuing to screen everyone every day. You know, we've done tests on playoff participants each week throughout the playoffs, and I don't think that will change. So, that screening will continue -- the same process that we've had in place.

Let's also understand that there's a culture of recognition within the team. I think if there's a player within the team environment or coach or staff member, who's displaying obvious symptoms, no one wants that individual to spread that around the team, particularly this week. But I do think that we saw this last year also, if you think back, we did not see almost any cases last year in the teams leading up to the Super Bowl – and remember that was at a time when everyone was tested every day and there were no vaccinations. So, I think that speaks to the fact that there's a lot of self-regulation of behavior in these playoffs and Super Bowl-bound teams. They're doing everything they can to keep themselves safe, staying out of harm's way and really avoiding risk exposures to make sure they stay healthy leading up to the game.

QUESTION: I have a question related to the hamstring injuries. Do you have a chart similar to the one you showed for the preseason, for the regular season and what the injury pattern was?

Sills: I don't think we have a chart on hamstrings available.

QUESTION: Just curious what – you saw that big spike in days 7-9, which if I'm recalling correctly, that's pretty consistent with what we see at training camp. There's always some magic with acclimation there. And I'm just curious, once you get to the regular season, if there's any other distinguishable spikes or patterns? And along with that, if you have any, obviously hamstrings are highly recurrent injuries, but if you have any data on the recurrence rate or recidivism rate, after somebody has returned.

Sills: Yeah, let me answer the first part of that. We do see somewhat of a spike of regular season hamstring injuries again in the first couple of weeks of the regular season compared to the rest of the regular season. I think we, again, are looking at that and how that relates to pre-season participation, particularly playing in preseason games. We think there may be a component of people needing to sort of get up to game-level speed, game-level intensity prior to starting the regular season. Again, there's more work to be done on that, but we are looking at that pattern. What we focused on today was just the preseason, because that's so much of a chunk of the problem during that first 10-day period. That's the natural place to start. As far as the second part of your question, let me toss it to Dr. Mack, because you used recidivism and that's kind of a big word for a neurosurgeon, so she's probably got a better answer. Christina, what about the recurrence?

Mack:  All LEX strains, we are very attuned to recurrence for them. They are one of the injuries that the players experience that is the most likely to occur for hamstrings. We often see that at 16% up to 20% recurrence rate and that's generally speaking. What's really important about your question, is we are really focused on bringing players back safely to the season and preventing those first strains in training camp. And then also as they come into the regular season, as Dr. Sills said, we do still see high numbers at the beginning of the regular season, because the key is getting people ready for that game-like intensity. So, if we can prevent those, then we are not only preventing those, but we're preventing those later in the season because to your point, the recurrence is really a point of focus. Bringing them back safely, giving them the time that they need and the treatment that they need to heal so that they don't have a recurrence is also a key point of focus.

QUESTION: In these final two weeks, has there still been spot testing and if so, how has that spot testing been conducted? In other words, will anyone be tested without having symptoms in the two weeks leading up to the game? I was also wondering about, has there been any self-reporting of symptoms in the playoffs that led to positive player tests?

Sills: There absolutely has been self-reporting of symptoms during playoffs among players, coaches, and staff. And we have seen some positive tests. Again, the overall numbers have gone down because we're just not seeing people that are sick, that are affected. That's a good thing, reflecting on this Omicron wave decreasing.

And the first part of your question was about spot testing and if we're still doing that. We've stopped random surveillance testing. We're only testing those who are symptomatic. Which, again, is a change that we made back with this targeted strategy in mid-December. We're comfortable with the results of that. Comfortable, that we've been detecting cases. And I think importantly, what we've been doing in health care all along and what seems to be working in that setting as well for detecting cases.

QUESTION: Do you have an update on either the number or percentage of players who ended up getting a booster shot at some point this season? And then the second part of that would be a little bit forward-looking. I understand a lot of this has to be negotiated with the Players Association, but what are the strategies, that you see moving forward in terms of vaccination and booster mandates and all of those sorts of things?

Sills: I think the latest figures are about 10% of eligible players are boosted. I think there are a couple of things that go into that. The rollout of the boosters really came at a challenging time for players. We all know that during the season players don't want to do anything that might detract from their performance or cause them to miss time, even if that's practice time. As you know, there's some people who will experience one or two or more days of symptoms when they get a vaccine or booster. I think it was challenging particularly since the timing of that came out toward the latter part of the season when every day really matters, and then going into the playoffs. It's something we'll continue to discuss.

We do know that all our league personnel and the clubs staffs were boosted. I think that it's safe to say that if we hadn't been that heavily boosted overall, that that Omicron would have hit us harder. Because if you look at the combination of staff and players, we're about 60% boosted overall in the NFL environment. If you look at the whole community with players, coaches and staff, it's about 60% overall that are boosted.

I think that helped us withstand this storm. I think boosters are the best protection. We'll continue to encourage them, but I don't think that we can project too far down the road yet to talk about what our protocols will look like. We'll sit down after the season, look at the data, track what happens over the coming months, and discuss that with the Players Association and their advisors and come up with what we think is best for next year.

QUESTION: Do you have any specific numbers on the number of positive tests during the postseason?

Sills: I don't have the total numbers in front of me. I have a couple of numbers just to give you a sense of the wave of what happened with Omicron. We look at it in weekly chunks. I mentioned that Omicron hit us about December 12th. If you looked at the following week, from December 19 to 25, we had 347 positive cases that week. Then the following week it went up to 411, and then the last week of the regular season, it came down to 216. Then the first week of the playoffs was 37 cases among the 14 teams. There's a rapid big spike and then a rapid fall off, which is what we've seen with Omicron around the world, in terms of how it hit and how it has receded. That's probably as close as I can come towards your question.