At least since the emergence of the omicron wave, it has been clear: you can get corona despite vaccination, and quite often several times. But is this the normal course of events with a virus that affects the respiratory system and not a cause for concern because the infection is becoming more harmless as some experts believe? Or is the increasing risk of reinfection a cause for concern?
The second opinion is now supported by a study that has not yet been reviewed, in which researchers looked at the risk of various secondary diseases, depending on how often those affected were infected with Sars-CoV-2. The result of the investigation was clear: the risk of suffering damage to the heart and lungs or of getting long Covid symptoms such as fatigue increases with every further infection.
Covie-19: Around 12 percent of those examined had already been infected twice
The team led by Ziyad Al-Aly from Washington University evaluated data from the US Army veterans’ health insurance company. According to the authors, this is the largest US healthcare system. However, 90 percent of the insured persons contained in the data sets are men, and women are therefore clearly underrepresented.
The scientists finally filtered out 257,427 people who had a confirmed corona infection. Of these, 36,417 (12 percent) had had Covid-19 twice, 2,263 (0.76 percent) three times and 246 (0.08 percent) four times or more. Then the researchers looked at the numbers of different complications in the six months following diagnosis and compared them to the respective incidence in a group of 5.4 million uninfected people.
Those infected more than once have twice the risk of all-cause death
Compared to those infected only once, the general risk of death doubled and affected around 23.8 out of 1,000 people in the group infected at least twice. The risk of being admitted to a hospital increased three-fold (95.5 people per 1,000). Damage to the respiratory organs or the cardiovascular system was twice as common among the reinfected, as were diabetes diagnoses or fatigue, mental problems, digestive disorders or other symptoms of Long Covid.
These problems occurred most severely during the acute phase of the disease. In many cases, however, they were still detectable six months following reinfection. The risk increased with each reinfection. “There was a gradual association, meaning the risk of adverse health outcomes increased with the number of infections,” the authors write.
Long Covid risks also increase with reinfections in vaccinated people
According to the authors, however, vaccination cannot reduce the risk of secondary diseases in the event of reinfection. The increasing risk was seen in unvaccinated, vaccinated and even boosted people.
