‘Breakthrough’ COVID-19 Infections: What to Know
Our primary care doctors in Delray Beach are getting questions from our patients about so-called “breakthrough” infections in those who have been vaccinated against COVID-19.
This is actually a misunderstanding. The term “breakthrough” implies an unexpected event, an infection that was able to breach some type of impenetrable barrier. But this is the wrong way to look at it. To understand why, let’s review how vaccines work.
How viruses get past a vaccine
The purpose of any vaccine is to prompt the body to recognize a harmful invader. Like a dress rehearsal for a play, it stimulates the immune system to prepare for “opening night,” so to speak.
Then, when the body encounters the real thing, it goes into action to defeat it. But it’s not an instantaneous process.
Sten H. Vermund, an infectious-disease epidemiologist and dean of the Yale School of Public Health compared this misconception to a bug zapper.
“As soon as it touches my [nasal] mucosa or skin or genital tract—boom, zap, it’s gone!” he told The Washington Post.
The reality, he explained, is closer to that of poisoned traps into which a pest might fall, wriggle around a bit, and eventually die from the insecticide.
An infection could happen anyway. It depends on how well your particular immune system is primed by the vaccine, how large an amount or what variant of the virus your body encounters, or what other chronic illnesses your body may be fighting.
“These variants are more transmissible, so they’re better at getting through the [vaccine] screens,” Sara Fortune, Chair of the Department of Immunology and Infectious Diseases at Harvard T.H. Chan School of Public Health, told NBC News.
“The other factor is how much virus is out there trying to get in, and that’s determined by the vaccination rates in your local community,” she added. “It’s how much virus you’re being exposed to.”
‘Breakthroughs’ are normal
Because no vaccine is 100 percent effective at preventing disease. Those who receive vaccines for other illnesses like the flu or measles may also become infected. Similar to how those who wear seat belts may also end up in a car accident. But you’re far less likely to be seriously hurt with the seat belt (or the vaccine) than without it.
“When people hear about breakthrough infections, they automatically think, ‘Oh, these vaccines are not working,’ or ‘they’re not effective,’ ” Richard Teran, an epidemiologist with the Centers for Disease Control and Prevention’s (CDC) Epidemic Intelligence Service, told Science News.
“That is just not true . . . the majority of individuals who do get the vaccine are protected against COVID infection and also against severe disease.”
And that’s the key.
According to the latest data from the CDC, about 6,600 severe cases of COVID-19 have been recorded so far. The number of people fully vaccinated is about 162 million.
Less than 0.004 percent of those who were fully vaccinated against COVID-19 have become sick enough to require hospitalization, CNN reported. And less than 0.001 percent have died from the disease.
Because the CDC is not currently tracking those who have symptoms mild enough to keep them out of the hospital, however, it’s been difficult to know how many actual cases of “breakthrough” infections have occurred in the fully vaccinated.
The vaccines are working
The Kaiser Family Foundation (KFF) undertook a study of official state data. It announced on August 2 that less than one percent of fully vaccinated people experienced a breakthrough infection.
That means that the vaccinations are providing 99 percent protection, even against the delta variant.
However, among the unvaccinated, fully 95 percent have been among those who were not vaccinated. A study in Israel of 152 breakthrough cases that required hospitalization involved people with underlying conditions like diabetes, hypertension, and congestive heart failure.
“The reality is that a lot of these breakthrough infections have been vaccinated people who test positive, but there’s a difference between testing positive and getting sick,” Angela Rasmussen, a virologist with the Vaccine and Infectious Disease Organization at the University of Saskatchewan in Canada, told NBC.
Masks can help
The CDC recently recommended that even those who have been fully vaccinated wear masks in public places. New research revealed that fully vaccinated individuals can transmit the virus even if they’re showing no symptoms.
While the agency received criticism for updating its May guidance, it actually means they’re willing to follow the science. If you were fighting a war and discovered the enemy had obtained a new, more lethal weapon, you would change your battle tactics. That’s what the CDC has done in recommending now that even vaccinated individuals should wear masks indoors.
The vaccines are almost miracle drugs in the way they’re preventing serious illness and deaths from COVID-19. And masks are an additional weapon in our arsenal.
We must use all the ammunition we have to get the virus under control. Every time the virus infects another human host, it could mutate into something that may be far worse. And then the vaccines may not work.
“Every pathogen arms race ends badly because this is fundamentally evolution,” Fortune told NBC News. “What we’re talking about is the virus trying not to go extinct, and evolution is going to favor transmission,” she said. “Evolution is going to favor vaccine escape.”