Early results from the clinical trials and observational studies of mRNA vaccines against SARS-CoV-2 indicated that not only were they highly effective at preventing symptomatic infection, but they were also effective in preventing asymptomatic infection and therefore transmission.2 (NEJM)
Guardian: It is likely that in the “before times”, few Americans knew that independent experts advised the US Food and Drug Administration (FDA) on the safety and efficacy of vaccines, and that the FDA usually took their advice.
Less than a year into the Covid-19 pandemic, that quickly changed.
The Vaccines and Related Biological Products Advisory Committee became arguably the most closely watched group of experts in America’s federal government. The media followed hearings, and thousands of Americans tuned in live to see whether these scientists considered Covid vaccines safe and effective.
“It’s really difficult, given the fact we never thought this [pandemic] was going to happen in this way … it’s all been a revelation,” said Monto. “And the revelation is also how societal beliefs would affect what we are seeing in terms of the continuation of severe disease.”
Ultimately, experts and Monto did say vaccines were safe and effective, and the FDA authorized Covid-19 vaccines for emergency use shortly thereafter. More than 237 million Americans have since received a vaccine. Through several more hearings, VRPAC has recommended vaccines to everyone older than five and booster doses to everyone older than 18.
Now, Monto is the author of a recent article in the New England Journal of Medicine, in which he considers the long-term future of the pandemic, and whether scientists can learn from another disease that was once pandemic – influenza. Read more..
After a period of falling Covid-19 illness rates, the recent spread of the delta variant of SARS-CoV-2 was a major disappointment and necessitated a reexamination of some previous assumptions.
This reconsideration may, at least in part, be a correction to overly optimistic views of what highly effective SARS-CoV-2 vaccines could accomplish. Some observers had hoped the vaccines could eliminate transmission of the virus, the ultimate goal of reaching herd immunity.1
A more likely picture of our future with this virus comes into focus if we examine the well-known infection patterns of another respiratory virus, influenza, both in and outside pandemics. That experience can help us reset expectations and modify goals for dealing with SARS-CoV-2 as it further adapts in global spread.
Early results from the clinical trials and observational studies of mRNA vaccines against SARS-CoV-2 indicated that not only were they highly effective at preventing symptomatic infection, but they were also effective in preventing asymptomatic infection and therefore transmission.2
The basic criterion used for emergency use authorization by the Food and Drug Administration was a standard one: prevention of laboratory-confirmed clinical infection meeting a case definition.
The effect on asymptomatic infections was a welcome surprise, because it has been thought that most vaccines for respiratory illnesses, including influenza, are “leaky” — that is, they allow some degree of asymptomatic infection and are better at preventing symptomatic infection. Read more…