Vaccinated people can become infected with COVID-19. But these breakthrough cases do not mean that the vaccine isn’t working.
On the contrary, statistics prove that they are doing their job—and that’s to protect against severe illness and death.
According to CNN, 49 states contribute data to the Centers for Disease Control and Prevention on the number of their breakthrough cases. Using these statistics and measuring them against the 164 million Americans who were fully vaccinated as of early August, the percentage of people who contracted COVID-19 is low. CNN analyzed the figures and found that 1,507 or fewer than 0.001% of vaccinated individuals died from COVID-19. There were 7,101 hospitalized patients, representing 0.005% of vaccinated individuals.
“The data suggests that more than 99.9% of fully vaccinated people have not had a breakthrough case of COVID-19 resulting in hospitalization or death,” says Dr. Sanjay Gupta, chief medical correspondent for CNN.
A Kaiser Family Foundation survey pointed out that none of the vaccines are 100% effective and that 95 out of 100 deaths caused by COVID-19 were among the unvaccinated or those not fully vaccinated. Dr. Gupta acknowledges that it is unsettling to learn that you can get COVID-19 even if you’ve had your inoculations but says that it’s not uncommon even with other vaccines.
“We don’t talk about flu cases and say we have ‘breakthrough’ infections, we talk about the efficacy,” says Dr. Carlos Del Rio, professor of medicine in the Division of Infectious Diseases at Emory University School of Medicine. “I think breakthrough has become a term equated with lack of efficacy.
Dr. Del Rio also said the vaccines were created to prevent serious illness and death, and that preventing infection was not the main goal. Immunologist and virologist Dr. Barney Graham, who was involved in developing the Moderna vaccine said that the vaccines were “designed to focus against disease in the lower airways (the lungs)—not in the upper airways (the nose and throat).”
Gupta explains that the vaccines trigger the release of immunoglobulins that act as antibodies to the virus.
“The main one generated by the vaccines is immunoglobulin G (IgG) which easily moves from the blood into the lower airways where it can block the virus,” he says. “The level of IgG in blood needed to penetrate the tissues of the upper airways is much higher and that is why it is more difficult to block the virus from growing in the nose.”
Dr. Graham, the deputy director of the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases, says, “That’s why we are seeing such consistency in the efficacy against severe disease.”
He also said “we got lucky” when scientists found that the vaccines also helped block infections with earlier versions of the coronavirus.
But with the more contagious Delta variant, Graham says we can expect more infections among both the vaccinated and unvaccinated populations. The difference will be in the severity of disease between the two groups.
According to CNBC, Professor Lawrence Young, a virologist at the University of Warwick’s Medical School in the UK, said the waning immunity may also be a factor in breakthrough cases as we go forward in this pandemic.
“We still don’t know how long vaccine-induced protective immunity lasts,” he says. “This is very likely to be a factor in those elderly and more vulnerable individuals who were vaccinated early in the vaccine rollout program.”
Young says that waning immunity coupled with the increased number of infections expected by the delta variant adds weight to the case for booster vaccines.