- As more people are vaccinated against the coronavirus, researchers will be able to see how well the vaccines work in the real world.
- Real-world effectiveness of vaccines is often lower than the efficacy seen in clinical trials due to a number of factors.
- Recent data from California and Israel find that cases are dropping as more people are getting vaccinated.
Last week the Los Angeles Fire Department reported a dramatic decrease in daily COVID-19 cases since firefighters started receiving the coronavirus vaccine in late December.
With around three-fourths of the city’s firefighter department members vaccinated, a memo from Fire Chief Ralph Terrazas reported that the department’s daily number of positive tests dropped from nearly 20 in December to less than 5 last week. The memo was originally obtained by the Los Angeles Times.
Experts say this is a sign that the coronavirus vaccines — which showed high efficacy in late-stage clinical trials — are also working in the real world.
So is the United States’ rollout of the vaccine also behind the declines in COVID-19 cases and hospitalizations seen last week in almost every state?
Experts say it’s unlikely, given that so far only 9.6 percent of Americans have gotten at least one vaccine dose.
“It is impossible to know the causes of the decline in cases and hospitalizations, given that [so few] of the population has been vaccinated,” said Dr. Sadiya S. Khan, an assistant professor of medicine and preventive medicine at Northwestern University Feinberg School of Medicine.
Other experts say these recent declines in cases are likely due to changes in people’s behavior — such as traveling and gathering less after the holidays, or wearing masks and physical distancing more in response to surging cases and news of hospital bed shortages.
But at some point, when enough people have been vaccinated, the country will start to see positive effects of the vaccine on the pandemic.
“If we are aggressive in rolling out the vaccine effectively, we can continue this downward trajectory,” Khan said. “This is especially critical right now as new variants that are more contagious are becoming more prevalent and could send us backwards, as we are seeing in Europe.”
Source: healthline