VaccinesHere's How the Three COVID-19 Vaccines Compare
With pharmaceutical company AstraZeneca’s announcement Monday that its vaccine successfully prevented coronavirus infection, three candidates appear to be promising vital tools to curtail the COVID-19 pandemic. However, scientists caution that all they know about these vaccines is what the companies have said in press releases. Like movie trailers, “They provide some exciting scenes but leave a lot unsaid. You have to go see the whole movie,” said Vanderbilt University infectious diseases professor William Schaffner.
With pharmaceutical company AstraZeneca’s announcement Monday that its vaccine successfully prevented coronavirus infection, three candidates appear to be promising vital tools to curtail the COVID-19 pandemic.
Biotech firm Moderna and drug company partners Pfizer and BioNTech announced last week that their vaccines were ready to submit to the U.S. Food and Drug Administration (FDA) for emergency use authorization.
They are signs of hope as the global death toll from COVID-19 nears 1.4 million people, according to Johns Hopkins University.
However, scientists caution that all they know about these vaccines is what the companies have said in press releases.
Like movie trailers, “They provide some exciting scenes but leave a lot unsaid. You have to go see the whole movie,” said Vanderbilt University infectious diseases professor William Schaffner.
More data will be available in the coming weeks, when the companies take their applications to the FDA. Until then, here is how the vaccines compare, based on the limited information presented in company press releases.
Efficacy
All three vaccines appear extremely effective.
The FDA told companies their products would have to be better than 50 percent effective to get emergency approval. All three far surpassed that mark while requiring two doses for maximum effectiveness.
Pfizer and Moderna both reported about 95 percent efficacy in their clinical trials.
The AstraZeneca vaccine was up to 90 percent effective, although one dosing regimen was less effective and reached only 62 percent.
However, the companies have not yet released all the data on how well the vaccine works in different age or ethnic groups, Schaffner notes, or for people with different medical conditions. The studies may be too small to answer those questions fully.
“The question is, effective in whom?” said Paul Offit, Director of the Vaccine Education Center at the Children’s Hospital of Philadelphia.
Studies have not yet been done on children or pregnant women, Schaffner noted.
The studies also will not determine how long protection lasts.
And they will not say whether the vaccine prevents infection, or just lowers the amount of virus enough to keep a person from getting sick.
If vaccinated people still can carry and spread the virus, “you still have to maintain mask wearing and social distancing et cetera,” Schaffner said, “which will make many people grumpy.”
