Lots of people highlighting pessimistic estimates of duration of protection for #COVID vaccines - but the facts guides us in the opposite direction: Im optimistic for multi-year duration of protection

Why?

1/n

1. Lots of the negativity comes from comparison to flu, where we need a seasonal vaccine.

BUT flu has a much higher rate of genetic drift, due to its split genome (on 8 separate DNA molecules) - #SARSCoV2 with its single molecule genome is mich more stable

2/n

2. Sequencing efforts confirm that #SARSCov2 S-protein is not showing much genetic drift across many,many cycles of infection

AND as we reduce the circulation of the virus with a vaccine, risk of genetic drift will decline further

3/n

3. More than six months after mass testing was introduced in multiple countries, the rate of PCR-confirmed reinfection remains vanishingly low

So natural infection has essentially 100% durability out to 6+ months…

4/n

… since durability will not fall off a cliff, but decline probably quite slowly, 100% durability at 6+ months must imply multi-year protection for the majority. Fantastic news!

5/n

4. Most vaccines show multi-year protection - in fact, flu is the outlier because of the genetic drift caused its multi-partite genome

If you can get a good, protective immune response to vaccine, then you almost always get DURABLE protection

6/n

5. The doom-mongers point to declining antibody levels after infection (or indeed vaccination) - but simple immunology tells you to expect that… the body doesnt keep churning out Abs against antigens it is no longer exposed to

B CELL MEMORY gives durable protection

7/n

6. And finally, it looks like T cell-mediated immunity is important in protection against #SARSCov2 and immunology tells us that is very long lived after exposure (although - important caveat - it may be strongest when you vaccinate young people)

8/n

So SIX reasons to be optimistic about the duration of protection afforded by #COVID vaccination - and NO reasons to be pessimistic (except, perhaps, that we havent YET got the data to PROVE durability)

But while we wait for the data, please spare us your unjustifiable pessimism!