Breaking down breakthrough COVID-19 infections
While vaccines are doing what they were designed to do — prevent severe illness, hospitalization, and death — very well, there are breakthrough cases. Dr. Andrew Badley, chair of the Mayo Clinic COVID-19 Task Force, explains.
As the COVID-19 delta variant continues to spread, many parts of the U.S. are seeing cases surge. While most severe infections and hospitalizations are among those who have not been vaccinated, breakthrough cases among those who have been vaccinated for COVID-19 have led many to wonder how concerned fully vaccinated people should be.
Dr. Badley says not all breakthrough infections are the same.
"I think it is misguided to lump all breakthrough infections together because they're very different," says Dr. Badley.
To put it into perspective, Dr. Badley breaks down breakthrough infections into three categories:
"Group No. 1 of so-called breakthrough infections are vaccinated people who, without any symptoms whatsoever, acquire infection, and it's diagnosed as part of routine screening," says Dr. Badley. "These vaccines were not designed to prevent that infection. These vaccines were designed to prevent hospitalization, severe illness and death. They do that very, very well. In a recent study that Mayo was associated with, the amount of death in vaccinated people was zero. So it's very, very effective at that."
"The second kind of breakthrough infection is a vaccinated person getting symptomatic disease," says Dr. Badley. "For a vaccine that is 90% effective, which all of these approved vaccines are more or less, you expect to see symptomatic infections in 10% of cases. The fact that we're seeing some of these vaccinated people get symptomatic disease is therefore expected."
"The third kind of breakthrough infection are those people with impaired immune systems," says Dr. Badley. "We don't expect those people to respond to the vaccine as well. In fact, that is why they were the first group recommended to receive the third booster dose. In those patients, through no fault of their own, they cannot respond to the vaccine as well as your normal host, for lack of a better word. Those are some of the people we're seeing going into hospital now. So when you consider the specifics of breakthrough infections, we can see that the efficacy of the vaccines in terms of what they are designed to do, which is to prevent serious illness, hospitalization and death, the efficacy remains very, very strong. These vaccines are behaving exactly as we expect them to."
Vaccination remains the best way to protect yourself from COVID-19, along with masking and social distancing.
Originally published on the Mayo Clinic News Network.