You’ve probably seen reports suggesting effectiveness of the Pfizer-BNT vaccine has dropped markedly in Israel in recent weeks, possibly because of waning immunity.
That claim may be wrong.
I think effectiveness has been underestimated, and this thread appears to confirm it.
The issue is that vaccination levels aren’t uniform in Israel. There are areas with very high coverage, and pockets where coverage is much lower.
A problem then arises if the country-wide average is used.
Israel’s fourth wave, driven by the delta variant, is only just starting to reach the people in the less vaccinated areas.
So until now, it was mostly vaccinated people who were getting exposed.
As a consequence, you’d see a lot of cases in vaccinated people - in relative terms - and not so many in unvaccinated people, because the virus couldn’t find any unvaccinated people to infect.
This made it look like the vaccine was no longer as effective as it used to be.
If this theory is correct, we‘ll start to see vaccine effectiveness “increase” again, as a greater number of unvaccinated people start to become infected.
Of course, immunity will wane eventually, and boosters will be needed at some point. But we may not be there yet after all.
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It’s also important to remember that these people first had to get infected and become a breakthrough case before they were at risk of developing long COVID.
Developing long COVID after vaccination is probably uncommon (but not rare).
The risk of becoming infected after vaccination should decrease as more of the population is vaccinated. Even if herd immunity isn’t reached, there should be some herd protection.
But until transmission is brought to low levels, it would be a good idea to keep wearing a mask. 😷
You know what worries me a lot more than COVID-19? People. Particularly angry, fearful people.
Make no mistake; they are afraid. Denial of reality is a coping mechanism for many. But you can’t avoid reality forever, and eventually they’ll turn on the enablers of that delusion.
The current crop of politicians who’ve promised freedom won’t be able to deliver it.
We’ll inevitably have to live with some level of restrictions until we have more of the world vaccinated with better vaccines. Will these people accept that?
But there’s a bigger problem. Many countries could have eliminated COVID-19 in early 2020 had they chosen to. It would not be a stretch to say that it was to an ideological choice to have a pandemic, to some degree.
Two new pre-print studies from Israel suggest the Pfizer-BNT vaccine is 80% effective against infection & 88% effective against transmission to household contacts. This is very good, but a significant proportion of vaccinated people can still get infected. medrxiv.org/content/10.110…
Researchers looked at the household contacts of confirmed COVID-19 cases.
7.5% of vaccinated household contacts became infected compared to 37.5% of unvaccinated contacts. medrxiv.org/content/10.110…
These studies were conducted at a time when the alpha variant was dominant.
It’s likely that effectiveness of the Pfizer-BNT vaccine against transmission is slightly lower for the delta variant.
I’m not confident the Sydney delta variant outbreak will be contained. This fundamentally changes the risk/benefit ratio of the AstraZeneca vaccine for those over 60.
Even a single dose provides >70% protection against hospitalisation & is worth the 0.00002% risk of blood clots.
(1/4) Study showing the B.1.1.7 (alpha/UK) variant is associated with a 52% increase in the risk of being hospitalised compared to the original strain. The increased risk mainly affects those aged 30 years and older. The risk of death is increased by 59%. bmj.com/content/373/bm…
(2/4) The authors also calculated the absolute risk of being hospitalised after testing positive with the B.1.1.7 (alpha/UK) variant.
For children (<10 years old), it was about 1%, and for adolescents, it was 0.7%.
This was not significantly different than the original strain.
(3/4) For 20-29 year olds, the absolute risk of being hospitalised was 1.9% (previously 1.5%).
For 30-39 year olds, the absolute risk of being hospitalised was 3.4% (previously 2.6%).