Story at a glance
- A study suggests that people can get reinfected with seasonal coronaviruses as early as six months after the first infection.
- The study uses serum samples from a long-term study and analysed data for 10 individuals.
- Although a small sample size, the results align with past knowledge that coronavirus immunity in humans is short-lived.
One of the main concerns for health experts working on the novel coronavirus is that if we can become immune to SARS-CoV-2 that the immunity may not last very long. Past research suggests that immunity may last anywhere from six to 12 months, and if COVID-19 becomes endemic like seasonal common cold coronaviruses it will continue to circulate around the world.
In a study published Sept. 14 in Nature Medicine, a group of researchers describe reinfection of seasonal coronavirus in adults. They looked for coronavirus antibodies in more than 500 serum samples from an HIV and AIDS cohort study that recruited men who have sex with men living near or in Amsterdam in the Netherlands. Participants gave blood samples periodically over several years since the study began 35 years ago. The samples were stored and brought out for this study.
The researchers found that reinfection with the same seasonal coronavirus could occur as early as six months later, and more frequently after 12 months. “What was surprising for us is that [reinfection] actually seemed to be a common feature for all the seasonal coronaviruses that we studied,” says first author Arthur Edridge to The Scientist.
WHAT YOU NEED TO KNOW ABOUT CORONAVIRUS RIGHT NOW
For the novel coronavirus, we’re still learning about what it does in our bodies, whether we have immunity and for how long. These are important questions for vaccine developers as well as public health experts. “Maybe it’s possible that if you only have these mild respiratory symptoms [with SARS-CoV-2 infection], you don’t develop a really strong immune response, and you could get reinfected,” says Rachel Roper, an immunologist at East Carolina University who was not involved with the study, to The Scientist.
If reinfection does happen, we will need to study how a second infection affects our bodies and whether it could be just as harmful the second time around. We don’t know yet if having antibodies prevents a more severe case if someone gets reinfected. Some experts think that if a vaccine for COVID-19 is successfully developed, people will need to be vaccinated yearly if immunity is not long-lasting.
The Nature Medicine study does support this theory but it also has its limitations. The researchers used data from 10 individuals in the study, which is a small sample size, because they had more than 10 years of follow-up. There is also a lack of diversity in participants in the study because the individuals were originally recruited for an HIV and AIDS study. The researchers were also unable to differentiate between strains. Although humans can get infected with four types of coronavirus, there can be many different strains of each.
“Caution should be taken when relying on policies that require long-term immunity, such as vaccination or natural infection to reach herd immunity,” write the authors. “However, antibodies are only one marker for immunity, which is probably also influenced by B cell- and T cell-mediated immunity.”
There’s still a lot we don’t know about the coronavirus, but we will continue to learn more as new studies continue to come out with results.
For up-to-date information about COVID-19, check the websites of the Centers for Disease Control and Prevention and the World Health Organization. For updated global case counts, check this page maintained by Johns Hopkins University or the COVID Tracking Project.
You can follow Chia-Yi Hou on Twitter.
BREAKING NEWS ABOUT THE CORONAVIRUS PANDEMIC IN AMERICA