Breakthrough Infections

My wife and I took our postponed 2020 vacation in Maine six weeks ago. COVID case rates were low. Maine, Pennsylvania, and Massachusetts, where our son’s house is the perfect stopover enroute to the Pine Tree State, had all relaxed restrictions for fully vaccinated people.

We ate most meals outdoors or at the cottage. We didn’t go to many crowded places. Going unmasked into a few stores and a couple of restaurants made me uneasy, but science was saying we would be reasonably safe and apparently, we were.

Back home, Lycoming County remained far below the target vaccination rate. News reports were full of the Delta variant, more than twice as infectious as the original virus, easier to catch than seasonal flu or the common cold. Infection rates, hospitalizations and deaths were rising, especially in areas where vaccination rates remained low. The Delta variant became the dominant strain in the country.

While we were in Maine a COVID outbreak in Provincetown, Massachusetts, made breakthroughs front-page news. Seventy-four percent of the cases were in fully vaccinated people! Taken out of context, the startling headline fueled misleading claims on social media.

“Breakthrough” sounds like what happens when the defensive ends or tackles get past the blockers to sack the quarterback. Or when invaders overwhelm a city’s defenders and its inhabitants. Did this happen in Provincetown?

The CDC (Centers for Disease Control and Prevention) defines breakthrough infection as “Development of a disease despite a person’s having responded to a vaccine.” “Breakthrough” seems to suggest that the vaccines aren’t working, that some perfect barrier between us and the virus has shattered. That’s not the case.

No vaccine is 100 percent effective. COVID-19 vaccines lower the chances of getting sick by over 90 percent. There will always be “breakthroughs” but overall, protection is high. However, vaccines are slightly less effective with Delta, making breakthrough infections more likely.

People’s immune systems differ. Some will be less protected by vaccination than others. Our genes, sex differences, inherited immune deficiencies, age, lifestyle choices and previous infections all affect our immune response to vaccines. The FDA just approved booster shots for people with cancer, HIV, and organ transplants. Because their immune systems are weaker these people are likelier to have “breakthrough” infections.

Vaccine effectiveness can fade over time, so we may all need boosters. Tetanus shots, for example, last about ten years. Reports that boosters may soon be recommended for everyone who has gotten the mRNA vaccines are circulating.

Three quarters of the Provincetown infections were in vaccinated people. “The vaccines aren’t working!” said the nonbelievers. They ignored the fact that the breakthroughs were 74 percent of a unique group of people in a particular set of circumstances, not 74 percent of everyone who ever got vaccinated. That only five of 469 infected people were hospitalized, and none died, was lost in the noise. Far from a vaccine failure, scientists say, the episode proves that the vaccines are doing what they should: keeping people from getting seriously ill or dying.

Constantly changing pandemic recommendations frustrate folks. “First you told us we don’t need masks, then you said we did, then you said not if you’re vaccinated, now you’re saying even if we are. Make up your mind!” Impatience is understandable, but science isn’t magic. It can’t have all the answers right away. Science asks questions, conducts studies, and finds answers, often leading to more questions and better answers. Science learns. Sometimes that means discarding old recommendations for new and better guidance. The process takes time.

The vaccines are very good at preventing severe disease and deaths. They are less effective at eliminating virus. New studies show that vaccinated people can carry as much virus in their upper respiratory tracts as the unvaccinated, confirming the suspicion that even vaccinated people can transmit the virus to others. People with the Delta variant may have a thousand times more virus than people had with the original. Unvaccinated people are highly likely to get sick from Delta.

The CDC now recommends that fully vaccinated people wear masks in public indoor settings in areas of substantial or high transmission, or anywhere if they or someone in their household are at increased risk for severe disease, or for 14 days or until getting a negative test result after close contact with someone with suspected or confirmed COVID-19.

And CDC recommends that all teachers, staff, students, and visitors to schools wear masks, regardless of vaccination status.

The pandemic news changes quickly because so many studies are being done and because the Delta variant spreads so easily. We must do everything we can to stop spreading COVID-19 around our communities- wear masks at indoor gatherings, social distance where appropriate, and above all, get vaccinated before a nastier variant than Delta comes along. Let’s end COVID!

Michael Heyd, a retired medical librarian from Fairfield Township who spent more than forty years searching the literature for professional hospital staff, is a member of Let’s end COVID!
Published: 8/21/21

Return to Articles