Reinfection with COVID-19 significantly increases the risk of death, hospitalization and other health problems, according to a study by researchers with Washington University School of Medicine in St. Louis.
The study, published in Nature Medicine, does not determine if these results mean that the patient suffers from long COVID. “Whether reinfection contributes to the increased risk of acute and postacute sequelae is … not known,” the study states. But it adds that “addressing these questions has broad public health implications since it will inform whether strategies to prevent or reduce the risk of reinfection should be implemented.”
Corresponding author Ziyad Al-Aly, M.D., of Washington University School of Medicine said in a press release that he’s concerned about what he perceives as “an air of invincibility among people who have had COVID-19 or their vaccinations and boosters, and especially among people who have had an infection and also received vaccines; some people started to refer to these individuals as having a sort of superimmunity to the virus. Without ambiguity, our research showed that getting an infection a second, third or fourth time contributes to additional health risks in the acute phase, meaning the first 30 days after infection, and in the months beyond, meaning the long COVID phase.”
Researchers obtained data on 443,588 patients in the Department of Veterans Affairs system from March 1, 2020, to April 6, 2022. They looked at 40,947 individuals with two or more infections, and 5.3 million noninfected individuals.
“We examined whether the risk of sequelae of SARS-CoV-2 reinfection was present in the acute and post-acute phases of reinfection,” the study states. “We conducted analyses examining risk and burden starting from the time of reinfection up to 180 [days] later in 30-day increments. Compared to those with no reinfection, those who had reinfection exhibited increased risk and excess burden of all-cause mortality, hospitalization and at least one sequela in the acute and post-acute phases of reinfection. The risks and excess burdens of all-cause mortality, hospitalization and at least one sequela during the post-acute phase gradually attenuated over time but remained evident even 6 months after reinfection.”
The study lands at a time when worldwide deaths from COVID-19 are down. Over 9,400 deaths in the world a week were linked to COVID-19 at the beginning of this month, compared to global weekly deaths of around 75,000 in February, the World Health Organization (WHO) announced recently. And that’s cause for optimism, which is the word WHO Director General Tedros Adhanom Ghebreyesus used in a recent virtual news conference. But not yet cause for celebrations or victory laps, as Tedros added “we continue to call on all governments, communities and individuals to remain vigilant. Almost 10,000 deaths a week is 10,000 too many for a disease that can be prevented and treated.”
Not only does COVID-19 reinfection do more harm than the first infection, but that harm increases with each subsequent infection, the study states. Al-Aly said that “this means that even if you’ve had two COVID-19 infections, it’s better to avoid a third. And if you’ve had three infections, it’s best to avoid the fourth.”
The study lands as the United States battles an early arrival of influenza and (RSV) that’s hitting children particularly hard and putting a strain on pediatric hospitals, a strain that could get worse as the country heads into the winter months and the accompanying indoor gatherings that spread disease.
Al-Aly says that “people should do their best to prevent repeat infections by masking, for example, getting all of their eligible boosters, staying home when sick. Also, get a flu shot to prevent illness. We really need to do our best to reduce the chance we will have a twin-demic of both COVID-19 and the flu this winter season.”