12/22—COVID-19 vaccines: the pandemic will not end overnight
COVID-19 vaccines: the pandemic will not end overnight
It will likely be a few years before the virus can be brought under control worldwide. Ideally, multiple vaccines will be approved in most countries and we will have a detailed understanding of their efficacy, the duration of the immunity they induce, and their effect on viral transmission. At the time of writing, there have been efficacy reports from phase 3 trials of five vaccines, but only two have been published in peer-reviewed journals.
Covid-19: New coronavirus variant is identified in UK
[BMJ news report.] Will the vaccine still work? The new variant has mutations to the spike protein that the three leading vaccines are targeting. However, vaccines produce antibodies against many regions in the spike protein, so it’s unlikely that a single change would make the vaccine less effective. Over time, as more mutations occur, the vaccine may need to be altered. This happens with seasonal flu, which mutates every year, and the vaccine is adjusted accordingly. The SARS-CoV-2 virus doesn’t mutate as quickly as the flu virus, and the vaccines that have so far proved effective in trials are types that can easily be tweaked if necessary.
Experts react to the new variant of SARS-CoV-2
[Expert opinion.] “Just because there has been a small change in the virus’ genetic make-up this does not mean it is any more virulent, nor that vaccines won’t be effective. Our experience from previous similar viruses suggests that the vaccines will be effective despite small genetic changes.” -Prof Tom Solomon, Liverpool
“Health Secretary Matt Hancock has linked the discovery of a mutation in the virus’ spike protein to increased transmission; while that is yet to be verified, it would be of grave concern if it indeed proves to be the case. While Hancock states that there is “nothing to suggest” this variant will cause more serious disease, if it spreads more readily than other versions, infecting more people, it could eventually take a bigger toll on human health.” -Dr Simon Clarke, University of Reading
China's successful control of COVID-19
“The speed of China's response was the crucial factor”, explains Gregory Poland, director of the Vaccine Research Group at the Mayo Clinic. “In China, you have a combination of a population that takes respiratory infections seriously and is willing to adopt non-pharmaceutical interventions, with a government that can put bigger constraints on individual freedoms than would be considered acceptable in most Western countries.”
Elimination could be the optimal response strategy for covid-19 and other emerging pandemic diseases
The typical approach of high income nations (such as those in North America and Europe) has been a “suppression strategy,” sometimes after initial use of a “mitigation strategy” (fig 1). The goal of suppression is to flatten the epidemic curve further than with mitigation, but still without expecting to end community transmission. These approaches are largely consistent with plans designed to mitigate or suppress pandemic influenza. By contrast, China’s success in containing the pandemic has shown that SARS-CoV-2 can be eliminated even after widespread community transmission. Several other Asian jurisdictions also achieved some success in containing the pandemic at an early stage, notably Taiwan, Hong Kong, and South Korea. The New Zealand government chose an explicit elimination approach. Australia also has elimination of community transmission as the stated goal, but has generally described its strategy as “aggressive suppression.” A related strategy that also aims to achieve zero community transmission is the exclusion approach that has been successfully used by some Pacific Island countries and territories (fig 1).
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