Vaccines currently authorized for use in the United States are highly effective at preventing Covid-19—but "breakthrough" infections do occur. Here's what to do if you test positive after being fully vaccinated, according to experts, Johnny Diaz writes for the New York Times. 

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Breakthrough infections are rare—and usually not serious

Research has shown that Covid-19 vaccines dramatically reduce the risk of contracting the coronavirus, and they also have proven effective in preventing hospitalization and death among people who are nonetheless infected.

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According to Eric Cioe-Peña, director of global health at Northwell Health, a vaccinated person who becomes infected with the coronavirus may have mild symptoms or even no symptoms at all.

Potential symptoms include nasal congestion and mild body aches. "It would be the mildest of the end of the spectrum of Covid-19," said Sunil Sood, a pediatric infectious disease specialist at South Shore University Hospital. "It may be just a mild common cold."

However, symptoms may be different or more severe for some vaccinated individuals, especially those with weak immune systems or those on certain medications. Further, although vaccinated people with Covid-19 are not believed to be as contagious as their unvaccinated peers, they still may be able to pass on the virus to others.

What CDC and experts recommend after being infected

CDC as of April 30 has recorded more than 10,000 breakthrough cases across 46 U.S. states and territories. Because CDC is currently recording only those breakthrough cases that cause severe symptoms, the total number of breakthrough infections is likely higher.

According to CDC, individuals who are fully vaccinated and are experiencing Covid-19 symptoms or who have tested positive should follow agency guidelines to keep themselves and others safe.

And as Cioe-Peña notes, those guidelines are not very different from guidance for those who test positive for Covid-19 prior to vaccination. In addition to isolating for 10 days, infected people should contact trace, wear a mask, and socially distance—with the understanding, Cioe-Peña added, that "your peace of mind is a little bit better."

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Individuals also should inform their health care providers that they have tested positive and receive guidance about what to do and when to retest if needed, Sandro Galea, dean of Boston University School of Public Health, said.

To prevent spreading the virus to others, CDC advises that an infected person should stay in a separate area of a home and use a separate bathroom if available. "If possible, maintain six feet between the person who is sick and other household members," CDC advises.

CDC guidelines also say that household items, including utensils, towels, and cups, should not be shared during the isolation period. Any surfaces that have been touched should be frequently disinfected. Turning on fans or opening windows and doors can also help increase ventilation into an area.

Experts emphasized that, even though breakthrough infections can occur in rare cases, currently authorized vaccines are highly effective and the best available way to prevent Covid-19—especially as more contagious variants of the coronavirus emerge.

"[Vaccination] provides a solid degree of protection," Sood said. "It provides the freedom to move around and go on with your daily life and activities almost before it was this pandemic." (Diaz, New York Times, 6/25).