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(Thread about COVID vaccines) More and more countries are rolling out their vaccination programmes. It is an amazing triumph of science that we have been able to efficiently introduce vaccines so quickly in so many places.
(1/n)
(1/n)
Currently, Israel is one of the front runners with more than 1.93 mln doses given (which counts both single doses and double doses given and does not account for the number of people fully vaccinated). That means more than 21% of their population and 72% of all 60+ year olds(2/n)
and 80% of all 70+ year olds have received the vaccine. We should watch Israel closely over the next week, as we should now be able to observe a drop in the number of critically ill older patients. (3/n)
Image showing predicted drop in critically ill in Israel from @segal_eran from the Weizmann Institute
The front runner in the European region is the UK with almost 3 mln doses given so far (this is mainly single doses, but not exclusively). (5/n)
I must admit that I doubted the feasibility of the governmentâs stated plan to vaccinate 2 mln people in two weeks but I must say that I have been pleasantly surprised. If we speed up a little more we may be able to vaccinate 15 mln by mid February as was promised. (6/n)
But, of course, some new media click-baits appeared in the meantime which need some explanation.
First of all - there is around a two week incubation period when it comes to COVID-19. (7/n)
First of all - there is around a two week incubation period when it comes to COVID-19. (7/n)
This is why it is so hard to contain - because you can be infectious for a very long time before symptoms appear. Unfortunately, getting vaccinated during this pre-symptomatic period does not protect you and you can go on to develop symptoms. (8/n)
Secondly, the first dose does not protect you immediately. Again, you need around two weeks before your immune system fully kicks in. And what is more, the first dose does not provide full protection. It varies from person to person and from vaccine to vaccine (9/n)
(in general the older the person the weaker the response after the first dose), but the average efficacy of the Pfizer-BioNTech vaccine is 52.4% between the first and second dose. I hope we all know basic maths and we know that 52.4% is not 100%. (10/n)
In that remaining 47.6% still lies the possibility of us getting infected and developing symptoms. After the second dose efficacy jumps to 95% which still leaves 5% but it is a really high percent of efficacy for any vaccine.(11/n)
If you heard that somebody developed symptoms after getting vaccinated that does not mean that vaccinations do not work. It means that they were unlucky and were either already infected asymptomatically or experienced that 47.6% (or equivalent). (13/n)
With the scale of the global vaccination programmes and the fact that we have third waves in many parts of the world, there may be quite a few similarly unlucky people. Still, vaccinations should protect you against getting COVID later and developing severe symptoms. (14/n)
This brings me to my last point. If you have already had COVID-19 you still need a vaccine. I previously posted an article stating that our immune response could last for several months after infection.(15/n)
But we are not all robots who came from the same factory, and in some percentage of people it wonât work the same way. Antibodies seem to wear off after around 90 days and we donât have straightforward, accurate ways to measure the level of protection given to us by the rest 16/n
of our immune cells, aside from these antibodies. As a result, we cannot say who is still protected and who is not after those 90 days. (17/n)
You have probably heard about some re-infections, and while some of them could be tests which picked up âdeadâ parts of the virus still present in your swabs, some are the same first infections which just did not get fully cleared by our immune system
some proportion might be actual re-infections. We know that around 10% of people might not be protected after their initial infection so please, go and get vaccinated if you can. It is the easiest way to be sure you are as protected as you can be.(19/n) https://science.sciencemag.org/content/early/2021/01/06/science.abf4063
Natural infection can differ in severity and can damage your organs. You probably donât want to get it twice. It also does not âtrainâ your immune system in the same way as a vaccine. It may leave you with a very weak antibody response which will disappear after 3 months. (20/n)
The vaccine does not give you COVID symptoms, and so wonât damage your organs and leave you sick for days. It can train your immune system in a safe and efficient way and so far we know that antibodies last for at least 8 months following vaccine administration. (21/n)
This figure is also only because clinical trials were around 8 months ago, it could easily last longer than that and tests to monitor this are ongoing.(22/n)
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