What is my current level of Covid protection?
September 18, 2022 9:02 AM   Subscribe

If I got a first Covid booster in October 2021 (all three Pfizer) but have not had a second booster, what is my current level of protection? I'm 50+. I'm not asking whether I should get the second booster, just what my actual current level of protection is.
posted by HotToddy to Health & Fitness (10 answers total) 2 users marked this as a favorite
It would be helpful for you to let us know if you have been previously infected, as that has bearing on your level of protection.
posted by citygirl at 9:26 AM on September 18, 2022 [1 favorite]

"Although COVID-19 booster vaccinations in adults elicit high levels of neutralizing antibodies against the Omicron variant of SARS-CoV-2, antibody levels decrease substantially within 3 months, according to new clinical trial data."

(Press release/high-level summary from the NIH, Jul 2022. The actual trial data is linked in the press release.)

A year out from your Pfizer booster, I'd suspect your current level of protection is slim-to-none against the now-dominant omicron sublineages. If you have been infected during or since the big omicron surge in January, that's a different story.
posted by basalganglia at 9:36 AM on September 18, 2022 [8 favorites]

Response by poster: No, to my knowledge I have never had Covid.
posted by HotToddy at 9:39 AM on September 18, 2022

The effectiveness of three doses of Pfizer, with the last dose more than 20 weeks ago, is nearly zero against infection, according to analysis from the UK Health Security Agency (page 6). This is probably not entirely correct, because it is very difficult to separate out the effect of past infection from past vaccination when nearly everyone has been infected, but it's pretty close to zero either way.

Effectiveness against hospitalization is probably about 50% (page 9) and against death somewhere between 80-90% (page 11). Same caveat as above applies to these figures.
posted by ssg at 9:40 AM on September 18, 2022 [13 favorites]

According to this podcast by the University of Minnesota Center for Infectious Disease Research and Policy:

For those 18 and older who are not immunocompromised, 3 doses of vaccine gives a person close to 50% protection against hospitalization near the time of recent dose; after 3 months, protection wanes to 35%.
Preliminary data for adults over the age of 50 who have received 4 doses show 60% effectiveness against hospitalization, and this drops to 55% after 60 days.

(Starts at 33.20 minutes into the podcast)
posted by SageTrail at 10:26 AM on September 18, 2022 [1 favorite]

looking like no protection against long-Covid/PASC.

That looks to be a study of people who already had PASC and then were subsequently vaccinated, to see if vaccination hastened recovery from PASC. I don't think it should be cited as evidence one way or another about whether vaccination prevents PASC. All of the participants already had PASC at the outset of the study.
posted by BungaDunga at 11:06 AM on September 18, 2022 [6 favorites]

You need to define what you mean by "protection". If you read the answers above carefully, you will see a distinction between "don't get sick", "don't need to be hospitalized" and "don't die from COVID". One reason Omicron is such a problem is that it is very quick so it is able to successfully infect people before their immune system has a chance to fully respond - even with vaccination and/or prior cases of COVID. That doesn't mean that the vaccination is useless - it still does a good job of keeping people from getting really sick.
posted by metahawk at 12:03 PM on September 18, 2022 [2 favorites]

i'm late 40s, had all three Pfizer shots, 11/21 the most recent. spent three weeks in the UK recently. wore an N95 mask religiously, got covid in the first five days. still can't smell or taste much despite testing negative for more than a week.

i'd say your level of protection from mild infection, as others have said, is pretty low to non-existent.
posted by hollisimo at 2:57 PM on September 18, 2022 [2 favorites]

Mod note: A couple deleted: 1) misinformation 2) nonworking link. Let's try to be careful with citations and claims attributed to them. Thanks.
posted by taz (staff) at 11:17 PM on September 18, 2022

Statistically, you are almost certainly smarter than I am, which means you might have a fighting chance at understanding this review, which discusses T cells and how they can provide immunity for longer than six months, though possibly in response to infection or even to strong infection, not vaccination
posted by troywestfield at 1:48 PM on September 20, 2022

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