- Evidence is trickling in that neutralising antibodies produced in response to vaccines, which were developed to target the Wuhan strain of SARS-CoV2, are considerably less able to neutralise the Omicron variant.
- Booster vaccinations can increase antibody levels to the point where they can neutralise even Omicron. Boosters also stimulate a better T-cell response.
- The highest levels of antibody are seen in people who have had a symptomatic Covid infection and are fully vaccinated.
- Level of protection (from infection) correlates with antibody level.
- T-cells primed by earlier variants retain much of their ability to prevent severe disease in people with the Omicron variant of Covid.
This is to paraphrase what was said in the programme. I do recommend listening to the podcast.
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bennevisplace
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So much misinformation out there. Too early to tell. One minute they say the new varient is not that dangerous & has only mild side effects. Then next they say its a fast speaker but our vaccines are effective.
Yes, we know little about the disease course of Omicron, except that it passes very easily from one person to the next. The number of Omicron cases in the UK (where until a week ago the Delta variant accounted for more than 99 % of new cases) is doubling every 2 to 3 days, so it seems destined to become the dominant variant, probably in many countries.
Yes indeed. We are waiting to hear that Paxlovid has been approved by the UK regulator. They were supposed to start the process about 1 month ago.
Our government has purchased 250,000 courses for the whole of the UK - to add to the 480,000 of Molnupiravir - i.e. not exactly an abundance. I know which drug I prefer.
I think the young demographics of southern Africa (not just South Africa), their low vaccination rate, and their previous experience with the Beta variant (B.1.351) make most assumptions about spread and severity premature for those of us in the US and UK. Note also that southern African has unusually low confirmed death rates per capita from Delta.
The numbers for spread depend to a great extent on testing and hospitalizations, which vary a lot from country to country, even for identical variants.
Severity depends a lot on age and immune system protection based on previous SARS-CoV-2 and other coronavirus infections. Those also vary by country and age. I've seen at least one page attempting show that common cold coronavirus protects children somewhat from severe infection. The common cold coronavirus variants change rather like influenza, although less quickly. This is a pioneering area for study.
Complicating everything is the fact that there a many different PCR tests. Some of the tests only identify Omicron because the come out negative, yet the patient has symptoms. So the sample then needs to be done on a different instrument platform. So, much of the case counts we're getting now are from particular labs, and are not a representative population sample.
Unfortunately, what we'll actually need are numbers based on actual infections, plus controlled studies of larger numbers (>100) of vaccinated and unvaccinated people in the US, UK, and EU. That will take weeks to months, depending on how quickly it spreads.
As an American, I am depending on the good figures coming from the UK, which has much, much better surveilance testing than we do.
In the UK we are in an "advantageous" position to monitor community spread of the Omicron variant. Although different labs handle PCR analysis, AFAIK they all use the same test. Because of O's "S-gene dropout" the PCR test is a quick and fairly reliable of distinguishing between Omicron and Delta, other variants being vanishingly rare here at present. I guess that a small random sample are subjected to genetic sequencing, but essentially the PCR test helps us keep on top of things. That said, there have been reports of a further mutation of Omicron that can't be so easily detected. Regardless, the test data leave no doubt that Omicron is considerably more transmissible, such that the number of infections is doubling every 2-3 days in England and less than 2 days in Scotland (that's an advantage of devolved health administration in the UK, we get 4 views of what's going on).
With regard to disease severity in the UK population the jury is still out. I agree we should not extrapolate the South African experience of mainly mild, there are too many confounding factors. It is striking how much lower the recorded Covid mortality rate is across the African continent compared with Europe, the Americas, and more developed Asia. My guess is it's largely down to demographics plus repeated exposure to common coronaviruses. If so, this would be cause for some optimism: cellular responses are broader and more durable than antibody responses.
I personally think it is a mistake that the AZ vaccine was discontinued in Canada and never launched in the US, but I ensured that my mom, sister and I got AZ as our first two shots and Pfizer as the booster.
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