If You're Vaccinated, Here are the Facts on 'Breakthrough' Infections

The best way to protect you and your family from COVID-19, and its more severe delta variant, is to get vaccinated. The vast majority of infections and hospitalizations are among the unvaccinated, but more vaccinated Americans are reporting they have tested positive for COVID-19.

The term — breakthrough infection — refers to someone who received one of the COVID-19 vaccines and has tested positive more than 14 days after they have been fully vaccinated. Even though these breakthrough infections are being reported more widely, they remain rare and generally mild, infectious disease experts emphasize.

Rare and Mild

Breakthrough infections are generally mild — and often asymptomatic. The vast majority of these cases do not require hospitalization.

“The vaccines protect you against severe illness and death — that hasn’t changed with the delta variant’s dominance,” explains Madeline Camejo, M.S., Pharm.D., chief pharmacy officer and vice president of pharmacy services for Baptist Health South Florida. “The surge we are seeing in hospitalizations is primarily among the unvaccinated in the age range of 25- to 50-year-olds.”

Dr. Camejo adds that public health officials recently reinstated most mask-wearing recommendations for vaccinated individuals because of the delta variant’s greater ability to be transmitted from one individual to another — even among those who are have received their full doses of vaccinations. 

“While the vaccinated are able to transmit COVID-19, especially via the delta variant, they are still protected from getting severely sick,” said Dr. Camejo. “Whatever variant is involved, there is no way to know how COVID-19 will affect you, even if you don’t have an increased risk of developing severe complications. So, despite breakthrough infections, you should get vaccinated.”

Sergio Segarra, M.D., chief medical officer at Baptist Hospital, said that those who are vaccinated should continue take necessary precautions. However, breakthrough cases should not deter anyone from getting vaccinated, including young adults who are healthy.

“Unfortunately, I think the progression of this disease will increase,” said Dr. Segarra. “We’re seeing a lot more mortality in younger, very productive, otherwise healthy people in our society. We’re stressed to very serious levels in our hospitals — and 90-plus percent of those are unvaccinated. And we’re seeing an increase in more breakthrough cases.”

Elderly, Immunocompromised Most Vulnerable

Infectious disease experts say the elderly, those with compromised immune systems, or those with underlying health issues, are most at risk for breakthrough infections. Aging and chronic diseases can impair the body’s natural ability to develop an immune response to an invading virus. Those who are immunocompromised because of an underlying illness often are not able to generate the amount of antibodies required to fight infections.

“The most vulnerable in the population, including older adults with compromised immune systems or other chronic conditions, should wear masks and continue to practice social distancing even after getting vaccinated,” says Dr. Camejo.

Those vaccinated who contract breakthrough infections may not know that they are infected because many don’t develop symptoms. For those who have been vaccinated and feel sick, the symptoms mostly don’t last as long and are milder than those who contract COVID-19 without being vaccinated. Those symptoms likely will include cough, fever, headaches and fatigue, according to recent studies.

Protection Against Delta Variant

Since the emergency of the highly contagious delta variant, researchers have learned that the vaccines provide effective protection against this now dominant strain of COVID-19. However, they add that breakthrough infections for those vaccinated are more likely with the delta variant — although severe illness and hospitalization remain very unlikely.

New research also provides a better understanding of the delta variant’s mechanism. The latest data finds that it can spread about two to three times faster than the original version of COVID-19.  Researchers also have found that the delta variant grows more rapidly inside the infected person’s respiratory tracts and to much higher levels.

“The delta variant makes it even more critical for everyone who is eligible to get vaccinated,” says Dr. Camejo.