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Related: Editorials & Other Articles, Issue Forums, Alliance Forums, Region ForumsVaccine efficacy: When covid-19 vaccines meet the new variants of the virus
A lot depends on blocking transmission not just disease
https://www.economist.com/briefing/2021/02/13/when-covid-19-vaccines-meet-the-new-variants-of-the-virus
On February 1st researchers around the world saw the tweet for which they had been waiting: We say with caution, the magic has started. Eran Segal, a scientist at the Weizmann Institute, had been posting regular updates on the course of Israels covid-19 epidemic since its mass vaccination campaign had begun six weeks earlier. By February 1st he was seeing the number of hospitalisations dropping significantly among the over-60sa cohort in which the number vaccinated had reached 70%, seen as a crucial level, three weeks before. After an expected but still somewhat nail-biting lag, the vaccine was doing its thing. By February 6th about 85% of the over-60s in Israeland 40% of the general populationhad received at least one dose of the Pfizer/BioNTech mrna vaccine (or in a few cases the Moderna mrna vaccine) and 75% of the over-60s had received their second dose, too. In that age group hospital admissions for covid-19 were about two-thirds what they had been at their peak in January and still falling (see chart 1). At the same time, the country as a whole was seeing its caseload rise.
The vaccine was not the only thing which arrived in Israel late last year. So did b.1.1.7, a highly contagious variant of sars-cov-2, the virus responsible for covid-19, which was first identified in Britain in September. It set about filling up hospital wards in Israel just as it has done in Britain, Ireland and Portugal. Despite an extended lockdown it is still doing so. It is no surprise that sars-cov-2 has evolved new biological tricks over a year spent infecting more than 100m people. But the near simultaneous arrival of not just b.1.1.7 but also b.1.351, which is now the dominant strain in South Africa, and p.1, a variant first seen in Brazil, is making the roll-out of mass vaccination more complicated and more confusing than might have been hoped when the first evidence of safe, effective vaccines became available last November. How fast the various new variants can spread, how well todays vaccines work against them and how soon new vaccines better attuned to themand to the other variants which will turn up over timebecome available will determine the course of the pandemic.
Testing the bounds
As of February 10th at least nine vaccines had been authorised for use in one or more countries. The Pfizer/BioNTech vaccine, first out of the gate, has now been authorised for use in 61, as well as for emergency use by the who. The number of doses administered, 148m, now exceeds the number of confirmed covid-19 cases recorded over the entire course of the pandemic. All of the vaccines appear very good at preventing severe cases of covid-19 of the sort that lead to hospitalisation and/or death; in trials which compared the vaccinated with control groups the efficacy with which the various vaccines prevented these outcomes was 85-100%. Their efficacy against all symptomatic cases of the disease found in trials has been lower, ranging between 66% and 95%. Some of that range is down to intrinsic differences between the vaccines. Some is down to trials being done according to different protocols and in different populations, sometimes against different variants of the virus. It is hard to disentangle such effects. The general message, though, is fairly clear. The vaccines make serious cases of all sorts very rare, and mild-to-moderate cases caused by the original strain of the virus a lot rarer than they would be otherwise.
That is undoubtedly good news; it lessens the death toll, the suffering and the strain on hospitals. But the situation is not perfect. For one thing mild and moderate cases can be worse than they sound. Many cases of long covid, a debilitating form of the disease in which some effects last for months, follow original infections that were not severe enough to require hospital admission. It is not yet clear whether long covid is less likely in people who have been vaccinated. What is more, this pattern of effects does not reveal what the vaccines are doing about transmission. As Natalie Dean, a biostatistician at the University of Florida, points out, there are two ways one can imagine a vaccine bringing about the pattern of protection the covid-19 vaccines have been seen to provide (see chart 2). In one of them the same number of infections occurs as would occur otherwise, but the consequences of these infections are systematically downgraded. Thus almost all of the infections which would lead to severe cases lead to moderate or mild cases, and many of the infections that would have led to moderate or mild cases produce no symptoms at all. The alternative is that the total number of infections is being reduced, but the ratio of severe to mild to asymptomatic cases stays roughly the same. The already low number of deaths and hospitalisations shrinks to something hardly there. The number of mild cases is similarly deflated (although, since bigger, remains palpable). And so is the number of asymptomatic cases. Indeed, the main difference between the two scenarios is that in one the asymptomatic cases rise, and in the other they fall.
The passing game.............
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Vaccine efficacy: When covid-19 vaccines meet the new variants of the virus (Original Post)
Celerity
Feb 2021
OP
The reason likely is that group has not been vaccinated to a significant level.
Blue_true
Feb 2021
#8
iemitsu
(3,888 posts)1. Seems like good news.
SunSeeker
(51,512 posts)4. Not if you're in the 0-59 age group like me.
Look at the New Hospitalizations graph.
iemitsu
(3,888 posts)5. Sorry, I'm older than that and just looked
the 65 + graph.
SunSeeker
(51,512 posts)6. The first person to die of Covid in the US was a 57-year-old woman.
https://www.sfchronicle.com/bayarea/article/First-U-S-COVID-19-death-was-57-year-old-Santa-15218813.php
Yet we're lumped in with the 20-somethings in terms of vaccine priority, i.e. dead last.
Yet we're lumped in with the 20-somethings in terms of vaccine priority, i.e. dead last.
iemitsu
(3,888 posts)7. Yeah, so much sucks about our situation.
Blue_true
(31,261 posts)8. The reason likely is that group has not been vaccinated to a significant level.
Hopefully, that is something that the so far good work of the Biden vaccine team can rectify.
Cal Carpenter
(4,959 posts)2. Thanks for posting this - lots of helpful info
Kick!
SunSeeker
(51,512 posts)3. What's scary is hospitalizations for ages 0-59 is shooting up.
I'm in the age group. It looks like it will be months before I can get vaccinated.
Blue_true
(31,261 posts)9. I saw a video appearance by Dr. Fauci.
The expectation now from him is that by April, anyone that wants a shot can get one. I will likely go in to CVS to get mine around that time. During the meantime, I will keep doing what I have been doing since last March.