Facebook poll suggests breakthrough infections are linked to long COVID

By Jocelyn Solis-MoreiraReviewed by Emily Henderson, B.Sc.Jul 27 2021

Vaccines have proven effective in limiting the spread of coronavirus disease 2019 (COVID-19) and reducing the number of severe COVID-19 cases that lead to hospitalization or death. However, how vaccines affect the risk of developing long COVID remains poorly understood.

Ongoing data from a poll via social media found that almost half of the fully vaccinated people who reported breakthrough infections also reported long COVID symptoms. In the study, one person with long COVID symptoms required hospitalization.

Poll Concept. Image Credit: Erta/Shutterstock.com

*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

The value of the survey is to highlight that some people report Long Covid following breakthrough and signals the importance of conducting more rigorous and detailed studies of whether risks of Long Covid after breakthrough are similar to what is being reported in initial infections.”

The study “Breakthrough Symptomatic COVID-19 Infections Leading to Long Covid: Report from Long Covid Facebook Group Poll” is published on the preprint medRxiv* server.

The study

The researchers worked with Survivor Corps — an organization providing support and resources to people with long COVID — to construct a public Facebook poll. The poll was first posted on June 2, 2021.

The poll invited people to report on whether they were infected or uninfected after getting fully vaccinated. The researchers specifically looked for responses on infections after vaccination and long COVID symptoms.

Some responses were not considered breakthrough infections if people reported infections less than 2 weeks after their second dose. In addition, people who were only partially vaccinated, had asymptomatic symptoms, or adverse reactions had their data excluded.

Risk of breakthrough infections and long COVID

The poll is still ongoing. The current study reflects the responses from July 22, 2021. About 1,949 respondents reported being fully vaccinated. About 1,024 people reported getting vaccinated with the Pfizer-BioNTech vaccine, 775 had the Moderna vaccine, and 150 had the Johnson & Johnson/Janssen vaccine.

Of the 1,949 respondents, 44 or about 2% became infected despite vaccination. About 19 people infected had received the Pfizer-BioNech vaccine, 17 had received the Moderna vaccine, and 8 had the Johnson & Johnson/Janssen vaccine. Of the 44 infected, 24 people had their COVID-19 illness develop into long COVID. Only 3 breakthrough infection cases in fully vaccinated adults required hospitalization. There was 1 person who had developed long COVID who needed hospitalization.

Study limitations

While the team’s survey showed evidence of breakthrough infections in vaccinated people, the researchers clarify that their study does not indicate that vaccines are not working.

There was a study limitation that warrants further investigation on long COVID symptoms and breakthrough infections.

The study relied on people volunteering to self-report their symptoms, so it is not likely that data on estimated rates of breakthrough infections or a person’s risk of long COVID could be accurately collected and assessed from the study.

*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.