With more than 161 million people now fully vaccinated in the U.S., experts say we are bound to see reports of breakthrough infections, meaning people test positive for COVID-19 while fully vaccinated.
“When you hear about a breakthrough infection, that doesn’t necessarily mean the vaccine is failing,” Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, said before Congress on Tuesday.
COVID-19 vaccines are highly effective, but they do not block the virus 100% of the time, meaning that some breakthrough infections occur after vaccination.
“I think people need to appreciate when you talk about breakthrough infections that the original data from the clinical trial — the efficacy data was based on preventing clinically apparent disease, not preventing infection, such as a symptomatic infection,” Fauci said.
Despite many high-profile cases of breakthrough infections with mild or no symptoms, including among Olympic athletes and some politicians, the overall number is very low compared to the number of people vaccinated.
That doesn’t mean severe illness as the result of an infection isn’t possible, but this tends to happen in people who are elderly or otherwise immune-compromised, experts said.
“Out of 157 million fully vaccinated in the US, there were 4,909 hospitalizations and 988 deaths,” Dr. Carlos del Rio, infectious disease physician and professor of Medicine in the Division of Infectious Diseases at Emory University School of Medicine, said during a press briefing on Monday.
“Of course we will see some breakthrough infections that lead to severe illness, more in vulnerable populations with underlying chronic conditions who couldn’t mount a response to vaccines because they couldn’t,” Dr. John Brownstein, an infectious disease epidemiologist at Boston’s Children’s Hospital and an ABC News contributor, told ABC News.
Although studies on this aren’t completed, Fauci said last week that the risk of a vaccinated person spreading COVID to someone else is assuredly far less than an unvaccinated person spreading COVID.
“You could make a reasonable assumption that the rate of transmissibility from the asymptom