With the highly contagious delta variant surging through the United States, breakthrough COVID-19 cases are causing infections even among the fully vaccinated. And, if internal documents from the Centers for Disease Control and Prevention obtained by the New York Times are any indication, vaccinated people can contribute to the variant’s spread. This is sparking questions about whether fully vaccinated people can come down with long COVID as well.
When it comes to breakthrough infections, fewer than 0.004% of cases have led to hospitalization, and fewer than 0.001% have resulted in death. It stands to reason, however, that developing long COVID symptoms could still be a cause for concern.
Long COVID symptoms can occur weeks after infection and persist for months. Symptoms may include shortness of breath, fatigue, skin problems, difficulty concentrating, and insomnia. In some cases, long COVID symptoms can develop even after a mild or asymptomatic infection. An estimated 30% of unvaccinated patients develop some form of long COVID.
Researchers are studying the possibility of long-term symptoms developing in vaccinated individuals, but the findings are currently inconclusive.
As noted by Slate, an absence of valuable data regarding long COVID and breakthrough infections is part of the problem. The CDC used to track all breakthrough infections, but the agency has, since May 2021, only tracked cases that lead to hospitalization and death. This decision was reportedly made to “maximize the quality of the data collected on cases of greatest clinical and public health importance.”
The lack of comprehensive data is leaving many wondering about long COVID among vaccinated people.
“In my opinion, CDC should be tracking all consequences of breakthrough cases, not just hospitalization and death,” Yale University immunology professor Dr. Akiko Iwasaki told Slate. “Even mild or asymptomatic infection can lead to long COVID. Tracking this on a national scale would be very informative.”
Iwasaki, one of the leading immunologists studying long COVID, is one of a handful of experts who have unequivocally stated that fully vaccinated people can experience symptoms.
Data is limited, but one small, peer-reviewed study out of Israel published by the New England Journal of Medicine on July 29 seems to back up Iwasaki’s conclusions. Out of 1,497 vaccinated Israeli health care workers, 39 breakthrough infections were found. 19% of those breakthrough cases reported symptoms including fatigue, headache, and muscle pain that lasted longer than six weeks.
These numbers suggest that the risk of breakthrough cases with long COVID symptoms is low. Early data and anecdotal evidence additionally seem to indicate that long-haulers may see improved symptoms after getting vaccinated.
Iwasaki’s findings indicate that up to 40% of long COVID patients experience relief from vaccination. She believes the reason may be attributed to dampening the autoreactive immune cells causing symptoms.
Researchers still don’t know why some symptoms linger and others do not, however. One theory posits that symptoms indicate lung scarring or damage to other organs from severe initial infections. Another suggests that symptoms result from the triggered immune response due to the virus lingering in the body.