Thread by @VincentRK

I hate to say this. But even as cases and deaths fall, COVID is not over: Get boosted. It is critical. Thread.

1/ In August last year, Malta became one of the highest vaccinated countries in the world. As cases rose with omicron, we thought deaths will stay low. They didn't.

2/ What happened? Did vaccines not work? Did the protection fade with time?

Well, we now know that vaccine efficacy after first 2 doses does go down with time. Malta raced to get everyone vaccinated. But when omicron hit, the population was >6 months out from initial vaccination

3/ Malta did recognize the importance of boosters early and offered them. But not everyone came and got the booster. There was also the small group of people who remained fully unvaccinated.

This is where most of the deaths are coming from.

4/ Half the deaths in age >60 are from people who didn't get the booster.

More striking: the 1% unvaccinated among >60
accounted for 16% of the deaths in that age group. @TheTimesofMalta

So the vaccines do work. If you take them. And even if you do, you need a booster.

5/ Conclusions:

- Boosters are essential
- Covid is so prevalent it invariably finds the susceptible people.
- A message for the world that we may see future big waves unless the booster effect is really enduring.
- We may need annual boosters.
- It's not over. Be cautious.

6/ Why were two doses of vaccine not enough. We were promised high efficacy. We were promised enduring efficacy.

-First 2 doses in retrospect were given too close to each other. Not enough time for true secondary immune response
-Second, variants can make vaccine less effective

7/ The pandemic came suddenly. Vaccines were developed with spectacular speed and efficiency. We are thankful for that. We now know a booster is needed. That's the nature of medicine We learn with time. With studies and observations.

If we need an annual booster, that's ok.

8/ I had said in July last year, Malta was a natural experiment in progress. It's important I follow through and explain what happened. Which is one reason for the thread. The second being the lessons we can learn and help save lives.

https://twitter.com/vincentrk/status/1420917686746370053

8/ You can read more here on the current wave in Malta. @TheTimesofMalta timesofmalta.com/articles/view/…

Another natural experiment in progress is in Denmark which removed all Covid precautions early. We can learn by following policy changes in other countries.

https://twitter.com/DrEricDing/status/1494700102904131586