The CDC’s paper https://www.cdc.gov/mmwr/volumes/71/wr/mm7104e1.htm#contribAff
Vinay Prasad, MD MPH; Physician & Associate Professor
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the cdc is back they have a new analysis in their own journal mmwr and this finally tells us the important answer to the question during the delta wave how much did vaccination protect you prior immunity from having been infected with the original alpha variant protect you or both protect you from subsequent hospitalization the title of the paper is entitled covet 19 cases and hospitalizations by covet 19 vaccination status and previous covet 19 diagnosis california and new york may through november 2021. what did they do here they basically combine two states data and they do a nice job of linking people who have been fully vaccinated early on in 2021 and linking them to the probability that they would get re-infected and hospitalized in the subsequent months of that year and the nice thing about this is that they’re able to delineate several cohorts people who are unvaccinated who never had covet 19 those are people walking around without any immunity at all people who are unvaccinated who already had coveted 19 people who are vaccinated and never had coveted 19 and people who are vaccinated and also had had covet 19 in the past so finally we get to see i think how protective vaccination is and how protective prior infection is against subsequent reinfection and hospitalization that’s what this paper shows you and the bulk of it is in the figure i’m going to show the figure right here on the screen the figure tells the tail and it tells the tale of what happens to these four groups during delta that line you see at the top the horrendous line showing a very high hazard rate is in fact being unvaccinated and having never met the virus before and if you’re around walking around unvaccinated and you never met the virus before you are at significant risk of hospitalization as shown in the picture over time that risk rises and falls i think with the epidemic wave that’s clear then are the next three lines and they’re bottomed out i think on the on uh pressing up against that x-axis they’re all the way bottomed out and those are vaccinated no previous covet 19 diagnosis that’s the dotted blue line that’s actually the highest of the bottom three lines and then unvaccinated but you’ve already had coven 19 in the past or vaccinated and you’ve already had cover 19 in the past and those are the two super imposable and bottommost lines on this graph what does that tell you this finally confirms something that i think a lot of people have known to be true and it’s been supported by israeli data but there’s been a lot of fragmented data on this question which is if you’ve had covet 19 if you have lived to tell the tale if you’ve recovered from it your probability of catching this virus again at least the delta strain and getting so sick you require hospitalization is very very very low it’s a very durable immunity against that severe outcome of hospitalization that’s what natural immunity gives you it also shows you that if you get an additional vaccine dose you also have a very very low chance of being hospitalized so that lends itself to many important questions which is who actually benefits you know among the people who’ve had infection and recovered who benefits from one dose or two doses or three doses and we’ve been trying to have that dialogue in a one-size-fits-all universe where cdc just basically ignores that information entirely and says you need to get the same as anyone else and they base that off and on antibody titers but i think what this shows you nicely is it really doesn’t matter what the antibody titers are the event you care about hospitalization is really bottomed out it’s floored by having had the virus and recovered from the virus um so i think there’s a lot more we need to do to tease out who are the people who benefit from additional doses of vaccine how many doses if you’re older it’s plausible that multiple doses after prior infection recovery will aid you but if you’re younger i think the question mark remains if you’re a 18 year old and you’ve had two doses and an omicron do you benefit from the booster that’s an open question that’s a question that paul offered himself has uh reservations about advising his own son not to do that the other thing i want to point out about this graph is it doesn’t tell you that you’re better off getting sick than you are to get vaccinated i think that would be a mistake to take that message away because this is the group of people who had gotten coveted 19 and lived to tell the tale they lived to tell the tale not everyone lived to tell the tale and that’s a big thing you know that’s a selection filter they’ve survived the virus they didn’t pass away from the virus i strongly suspect and i think there’s a lot of data that would support this for the vast majority of people who have not yet met the virus who don’t have natural immunity it is the much preferable route to get the first dose of vaccine rather than meet the virus without any immune system in fact you see the hospitalization rate for people who didn’t do either they’re just the tall blue bar on that figure so i think it’s a mistake you know two things can both be true you if you have no immunity against the virus it’s in your best interest to get vaccinated but also we can have more nuanced policy among those who happen to have been infected and recovered in terms of subsequent doses and how many doses they might need and benefit from and that might vary by age medical problems and a whole host of other things including how recently they were infected so this shows that very nicely i want to show you one more figure from the supplement and um i’ll pick the uh the new york state figure this shows you and i wish it had included the people who are unvaccinated but it shows you the new york state figure no prior covid three lines um and whether you got the j and j vaccine the moderna vaccine or the pfizer vaccine and prior covet 19 and you got the j and j moderna or pfizer and i think what you see clearly is if you had not yet been infected and you had gotten one of those vaccines there’s some breakthrough rate of infection and that’s shown by the blue the gray and the orange line and what it shows you i think is that moderna is superior and pfizer is second place and j j is in third place which is where j j has always been and nobody who has a big fan of j and j and now j j is actually advised not to be the preferred choice so j and j sorry sorry jansen sorry johnson johnson not so good um the three lines show that if you have had a prior infection you know they’re rather indistinguishable in my opinion um which tells you that you know that and i would love to see that line prior infection but you know not received any of these vaccines at all that would have been great to add to this plot but i think it does give you some information about the differential value of vaccines so back to this i think and there are some pundits who said very strongly that natural immunity would not provide a robust protection against hospitalization in the wake of delta i think these data show conclusively that that is wrong natural immunity does provide robust protection in the wake of delta i think these data may be misinterpreted to mean you ought to seek out exposure to the virus rather than seek out exposure to the vaccine if you have not been exposed to either i think that would be a mistake i mean it’s actually there’s no way the data can actually show that one way or the other but certainly that would be the erroneous conclusion from this data bull right i think it does show is that vaccination although terrific is not as good as prior infection and recovery in terms of preventing hospitalization those are actually the floored events um but of course the worst way to be is to be both on have no natural immunity and uh no vaccinations in you then you’re a sitting duck for this virus even in subsequent waves that may even follow today’s date so the cdc has finally you know i think they finally disambiguated a few things we spent so much time seduced by antibody titers and they published papers saying that well you know the antibody titer is higher if you did if you had natural immunity you got a dose of vaccine but that’s kind of a tautology i mean of course it would be the case that more antigen will transiently boost antibody titers that’s not what i really care about what i care about is proving to me that that increase in titer leads to a durable reduction in hospitalization severe disease what these data show you is that having recovered from natural infection is really really good it’s really good it’s hard to improve upon that it’s already really good when it comes to hospitalization and so i commend the authors for publishing this i commend mmwr for putting it out there and i think it will vindicate a lot of people who feel like natural immunity is not properly incorporated into our vaccination guidelines and i think it does vindicate them so if you like this video you know what to do like subscribe comment leave a message below uh that’s my take of the paper i think kudos to the authors they nicely pooled a few data sets together they’re looking at clinically relevant endpoints which i like to see um you know what would be even better well even better would be to run a number of randomized control trials in every single one of these groups natural immunity being randomized to different doses and different strategies of vaccination including one two or or even three doses to have enough power in those randomized control trials to see interaction by age or comorbidity that would be the gold standard and in fact companies have a lot of money and the fda could have compelled them to do that but instead we have a very low regulatory standard which is something i have quite a problem with and i’ve written a couple books about so you know what to do like subscribe comment leave a message this is my take on the january 19th mmwr report there’s another one i want to do to be continued so until next time
