Vaccines Offer Strong Protection Against Long COVID, as Confirmed by New Large-Scale Study

A population-based cohort study conducted in Sweden has revealed that COVID-19 vaccination significantly reduces the risk of developing long COVID, also known as post-COVID-19 condition (PCC).

This study was published November 22 in BMJ and examined data from 589,722 individuals. It found that those who were vaccinated had a lower incidence of long COVID compared to those who were unvaccinated.

“The results very clearly demonstrate that people should continue to get vaccinated for COVID-19, and obtain their complete COVID-19 regimen, for long-COVID prevention,” Dustin Duncan, Sc.D., told MHE.

Duncan is an associate professor of epidemiology at Columbia University Mailman School of Public Health. While Duncan was not involved in the study, he shared his insights on the findings with MHE.

The study included adults diagnosed with COVID-19 between December 27, 2020 and February 9, 2022. Among the 299,692 vaccinated individuals, only 0.4% were diagnosed with long COVID during the follow-up period. In contrast, among the 290,030 unvaccinated individuals, 1.4% developed the condition.

Overall, the study found that vaccine effectiveness against PCC was 58% for individuals who received any number of vaccine doses before initial infection.

Furthermore, each additional dose of the vaccine received before infection was associated with additional protection. Specifically, the effectiveness was 21% for one dose, 59% for two doses, and 73% for three or more doses.

These findings highlighted the importance of vaccination timing, showing that individuals who received their vaccines before infection had a reduced risk of developing PCC. The study adds to the growing body of evidence that supports the protective effect of Covid-19 vaccination against PCC.

Previous studies based on self-reported symptoms have suggested higher rates of PCC, indicating that the actual prevalence of the condition may be higher than reported.

One of the strengths of this study is its large sample size, which provides robust findings. However, like any observational study, it has limitations. This research relied on national register data and was unable to account for certain variables that may have influenced the results.

Additionally, the study focused on a specific population in Sweden, and the findings may not be applicable to other countries. Note that this study focused on the COVID-19 vaccines that were available during the study period, which did not include the newer boosters that became available this fall.

“Continued public health campaigns are sorely needed for COVID-19 vaccine uptake, and we need to focus on health equity,” Duncan stated. He explained that vaccine-promoting efforts need to focus on marginalized and minoritized populations due to ongoing disparities in long-COVID.

“For example, where Black and Latinx adults in the U.S. are more likely to experience long-COVID symptoms, vaccination campaigns should be targeted and tailored to sub-groups that experience inequities for health equity. [These] campaigns should address documented barriers such as medical mistrust and vaccination access including due to lack of health insurance,” he said.

“By focusing on barriers specific to marginalized and minoritized groups, while also using culturally congruent health communication approaches, such as culturally relevant language and images, we can increase overall vaccine uptake, especially among those who need it the most,” Duncan explained.