A third shot of a COVID-19 vaccine raises immunity. Will you need one?
Also side effects to COVID vaccines and the risks of social media
There’s a frontier of stories that change with every news cycle that make it seem like you should be doing something different every moment. This makes it seem like intractable variants are emerging every day, that vaccines are ineffective, and that the pandemic will continue indefinitely.
But I urge you to stop for a second to think about how the latest news story that you read relates to anything actionable that is within your power to change. I say this as someone who has read over a thousand articles on COVID-19, and has written a book and a dozen or so articles on COVID-19.
If you are an adult who is not vaccinated yet, the best thing that you can do is to get your prime and booster shot as soon as you are eligible and vaccines are available to you. A vaccine with 60% efficacy in your arm will help you more than a vaccine with 95% efficacy that is out of reach now and possibly for the next few months.
If you are already vaccinated, take appropriate precautions (mask-wearing, hand-washing) to prevent infection and transmission in the light of the more transmissible Delta variant and its spawn.
What about a mix-and-match approach to vaccines? I wrote about it for Hindustan Times and there’s more information in an article in the Lancet.
Here’s a summary: Two doses of Pfizer/BNT elicit the highest antibodies, but one shot of AstraZeneca followed by Pfizer was virtually indistinguishable to it. Pfizer followed by AstraZeneca or two shots of AstraZeneca were lower in the number of antibodies.
Note that in all cases, the vaccines are effective to varying degrees.
Do you need a third shot of a vaccine right now?
Edit (November 20, 2021): Nearly four months after this newsletter was written, based on new data on neutralizing antibody levels, the F.D.A. announced that any adult can get a third shot of any mRNA vaccines in the U.S.
Yesterday all of Twitter was reacting, as Twitter does in knee-jerk fashion, to reports of a third shot of AstraZeneca raising immunity.
That’s great news, but do you need it now?
Prof. Andrew Pollard who led the study was very clear that you don’t and that this is preparing for a future outcome that may or may not come to pass.
Boosters are much more about if protection gets lost over time – and we don’t know that – but if it does, could you boost? And the answer to that from these data is yes, you could.
There’s no indication today that we need boosters, and it is something where we need to keep looking at the data and make decisions as the months go by, about whether that protection that we have is lost.
Will you need one in the future?
No one knows for certain yet and it depends on 1) how long immunity post-vaccination lasts, 2) how much the variants continue to mutate to escape from immune responses, 3) your age and risk factors, 4) which vaccine you received first.
So far research has shown that post-vaccination immunity (after receiving one of the two mRNA vaccines) is long-term and likely lasts a year or more, is capable of dealing with all current variants without a third shot, and induces a strong immune response in all major age groups with high levels of effectiveness. At the moment, a second booster shot is not required. And it may be that a booster shot is not required in the future for all age groups or people.
Experts have told us for over a year that SARS-CoV-2 is never going away completely. It will remain endemic in human populations. That is different, of course, from the pandemic ending. The pandemic will end. All pandemics end.
I think it is premature to predict that everyone will need a boost every year like flu shots. You cannot compare a new pandemic-causing virus (and variants) to seasonal influenza that has defined patterns (and alternate spikes in the northern and southern hemisphere).
In an interview with NPR’s Short Wave, the director of the National Institute of Health, Dr. Francis Collins revealed his thoughts on the topic:
AUBREY: You know, that is possible. I mean, it's well known that as people age, immunity is not quite as good. Already, we see older people get a higher dose of the flu shot. So it's reasonable. But scientists may see some people having more durable immunity to the coronavirus. And even beyond age, there could be variability. Dr. Collins says the promise of personalized medicine is to be able to assess this.
COLLINS: If we come up with a really reliable way to assess whether somebody's immunity is still good enough to provide protection, might we be in a place where instead of saying, OK, everybody, after one year, you should get a booster, maybe we'd have an actual simple test to say, OK, you're one of those people that should get it at nine months and you're one of those people where, gosh, it looks pretty good. You could wait another year before you get a booster. That'd be a really efficient way to do it.
On an ethical level, I think it will be incredibly unfair if healthy low risk people get access to additional boosts, while a sizable part of the world remains completely unvaccinated and completely susceptible.
With that said, there is one particular case where a third shot is helpful. A second boost (three doses) of the same vaccine has shown promise in certain immunosuppressed people who are solid organ transplant recipients.
Here's a useful heuristic: vaccines work against variants until they have been shown NOT to work effectively.
We are developing boosters in case they are necessary in the future. Worry about the future, once you have taken care of the present by getting two doses of an available vaccine.
What I’m reading:
Side effects to COVID-19 vaccines should be welcomed “as a necessary prelude to an effective immune response.”
But if you don’t have side effects, then you shouldn’t worry either.
Why some biologists and ecologists think social media is a risk to humanity.
One of the smartest people I know on Twitter has written a great paper on the risks of social media. This is a great interview.
What I’m watching (besides the Euros and Copa America):
"Science is a process."
This is a great video under two minutes that explains the process and what questions to ask when you see scientific claims.
Thank you for sharing about booster doses.
Thank you for sharing information about booster requirements. After reading your blog post i feel relieved.