Length of vaccine efficacy

6 months

I hope they figure out what to do in June-July timeframe when first group’s vaccine begin to expire.

the vaccine on have reached 6 months of antibodies after the second shot.

I would be satisfied if the immunity period reach 12 months. That would put the Covid vaccine on the same footing with Flu vaccines, annual shots.

It will mean having to go twice to get flu and vaccine because they won’t give them both at the same time.

My guess is the Covid vaccine will migrate to a single shot, and won’t require the ultra-low temperatures it now does.

In fact the Novavax vaccine is not only a single shot, it can be kept in the same refrigerators as Flu vaccines. That vaccine has not yet been approved for use, but likely will soon.

Pfizer appears to be angling toward a single shot, regular temperature vaccine, it recently announced that it will pursue it’s own path in regards to a follow-up to it’s current Covid vaccine. Pfizer has lots of money, the company own some popular and lucrative regular consumer product brands, like Chapstick (the lip balm and lip color biggie).

So, the future won’t look like today. My guess is pharmacies will be able to easily manage an annual Covid and Flu vaccine regimen, and the process will be easy for us.

The influenza vaccines are targeting different strains of influenza. The influenza antibodies remain longer than a year - it is just that next year's strain is different from this year's.

This question is about whether the antibodies against COVID (created by a non-traditional path) remain beyond 6 months.

We don’t know how many variants of Covid that study participants have been exposed to, but previous studies have shown the vaccine to be effective against several variants, somewhat less effective against others. So, a reasonable assumption would be that immunity duration follows effectiveness against variants (a person that have long term immunity to one has it for others).

A one year interval for a shot is the easiest interval to execute. Longer or less than a year becomes difficult to manage (people will lose track of whether they have the vaccine easier).

They are two different questions, each of which plays into how long a particular vacicine will last.

One is how long the antibodies last (similar to other single-illness vaccinations, many of which need boosters periodically because the antibodies diminish over time - like tetanus, for example.)

The other is whether the variants are enough different that the (still plentiful) antibodies are no onger effective against the variants.

As to influenza, the antibodies are pretty specific - so it isn't that the antibodies are gone in a year, it is that influenza changes dramatically and unpredictably from year to year. The antibodies you develop in one season aren't effective against the influenza next year not because they vanish, but because the disease is different next year. Because we suck at predicting the strains that will be circulating, the antibodies generally aren't even effective against the current year's strains.

COVID 19 makes much more minor changes (the variants) and the vaccine is creating antibodies to the spike protein that (so far) all variants have in common. So if the antibodies last for 10 years, the vaccine will be effective against all variants for 10 years (unless the variants change significantly enough that the antibodies don't recognize the spike as the old familiar enemy.

My guess is that along the way, the level of immunity to all variants will be determined.

Influenza vaccines are a once-a-year thing because it's not the same flu next year as it was this year. The vaccine doesn't wear off - just as you wouldn't expect a chicken pox vaccine to protect you against measles, or even against shingles, this year's influenza is enough different from last year's that you need a different vaccine. The antibodies you create from this year's vaccine can ast forever - and you'll still need a new vaccine next year.

That does not appear to be true for COVID 19. So the question as to COVID 19 is really much more about how long the antibodies last.

So COVID may be a once a year, or once every 6 month thing - BUT if it is, it will be for a very different reason.

The issue we have now is that the COVID 19 vaccine is so new that we have no idea how long the antibodies last. We still don't even absolutely know whether it decreases the severity of the disease or whether it prevents it (although 2 or 3 recent studies suggest it prevents disease).

So yes - ongoing studies are needed to determine how long it lasts since it hasn't been around long enough for us to know how long it lasts. When my brother was part of the initial MMR trials (as a captive Native American in the adoption/foster care system), we assumed that the vaccine created immunity for life. It was only after a couple of decades, when we started having people who were pregnant contract ruella that we realized that the antibodies didn't last that long.

Studies are also needed to answer the second (variants) and third (disease prevention v diminished severity) questions.

My only point is that seasonal strains of influenza (which generate the need for new vaccines every year against the distinct strains) and COVID variants (which, so far, are not distinct enough to require a new vaccine).

I don't think they tested much further than that yet.

The clinical trials started last summer, I think, so even those participants will have been vaccinated for less than a year. I haven't heard if any of them are getting the virus.

[link:https://www.usnews.com/news/health-news/articles/2021-04-01/pfizer-coronavirus-vaccine-protection-lasts-at-least-six-months|


I'm guessing that it will be like the flu shot - dealing with variants and strains every year.

CDC must've have a pretty good reason for including so many extra entry areas on those cards - they likely surmised frequent boosters would be required, and based on the latest I read that Pfizer is claiming 6 months of protection, that seems to line up.

https://www.washingtonpost.com/lifestyle/2021/03/29/how-long-immunity-lasts-covid-vaccine/

Ummm....! Not only was I surprised when my husband told me this, but, I assume there is a plan??!!

That would suggest that there's a high possibility of immunity going well past that 6 month time frame. In my mind I see a yearly booster for a while.

I believe the company is following a group of the people that it tested the vaccine on. The study is ongoing, so the immunity period can be longer than 6 months.

This is of interest, though.

https://www.news5cleveland.com/news/national/coronavirus/new-test-looks-to-monitor-antibody-levels-after-covid-19-vaccine-shot

if we need booster shots, what will be the cost of them?

we are not further along than a year ago

I suspect that COVID19 may need similar protocols, as it is a virus that mutates rapidly. But I am not an epidemiologist.