If Your Coronavirus Case Is Mild, It's Not All Good News, Study Shows

A milder case of coronavirus may mean you're not as protected against re-infection in the future.

One of the scariest things about coronavirus is how wide-ranging the illness' symptoms can be, running the gamut from a mild cough to major organ failure. And while having mild symptoms may seem preferable, new research suggests that having a less severe case of coronavirus could shorten the period during which you're immune in the future.

According to a July 21 report published in The New England Journal of Medicine, antibody levels declined rapidly among 34 study subjects who had mild cases of coronavirus in which hospitalization was not required. Their antibody levels were taken at an average of 37 days after they first experienced symptoms, and again at 86 days after becoming symptomatic. Among the patients studied, the half-life of their coronavirus antibodies (the period of time in which it took the antibodies to diminish by 50 percent) was just 73 days.

So, what does this mean in terms of the potential for reinfection? While the study's authors suggested that antibody decline would likely slow after the 90-day study period, they also noted that the short period of immunity in subjects with mild coronavirus could present complications in terms of both future social transmission and vaccine efficacy.

white hand getting blood draw for coronavirus from doctor or nurse wearing gloves

Specifically, researchers cautioned against the use of so-called "immunity passports," in which individuals could present documentation of their coronavirus antibodies, thus allowing them to head back to work, travel, or participate in other social activities.

The rapid decline in coronavirus antibodies among patients with mild COVID-19 cases also presents possible issues in achieving herd immunity, which occurs when the majority of a population becomes immune to a disease through either infection or vaccination, thus limiting their potential to transmit the disease to those who haven't yet had it or haven't been vaccinated. Since infection or vaccination may only confer immunity for individuals who had mild coronavirus for just over two months, this could mean that they're more susceptible to re-infection or could inadvertently spread the virus to others.

RELATED: For more up-to-date information, sign up for our daily newsletter.

While multiple studies have discovered higher levels of coronavirus antibodies in patients who've had severe cases, that doesn't mean you can assume you won't transmit COVID-19 to others after being seriously ill with it. In a not-yet-peer-reviewed July 11 study led by researchers at King's College London, antibody levels began to decline after approximately one month in most patients, regardless of their case's severity. And if you're wondering which areas of the U.S. have low antibody levels, 95 Percent of People in These States Are Still "Very Vulnerable" to COVID.

Sarah Crow
Sarah Crow is a senior editor at Eat This, Not That!, where she focuses on celebrity news and health coverage. Read more
Filed Under