DETROIT – For many COVID-19 survivors, one comforting thought has been that at least you might have some immunity to future infections. But that might not always be the case.
There are two new reports of people in the United States becoming reinfected. The first documented case of a COVID-19 reinfection was from Hong Kong. Since then there have been scattered reports from other parts of the world. In most of those cases, the second infection was not as severe as the first. Now, two U.S. cases are challenging that.
The first U.S. report of a SARS-CoV-2 reinfection was published in the Journal Lancet Infectious Diseases. The patient was a healthy 25-year-old resident of Nevada who initially tested positive on April 18. At that time, he had mild symptoms of sore throat, cough, headache, nausea and diarrhea.
Nine days later his symptoms were gone and repeat tests for infection were negative. On May 28, weeks after his initial infection, he became sick again. He tested positive again for COVID-19.
This time though, his symptoms were more severe and he required oxygen. The researchers are confident that this was a reinfection, not a relapse. The genes from this first and second virus were different.
A second U.S. reinfection was also published in the Journal Clinical Infectious Diseases. That patient was a healthy 42-year-old Virginia Military Health Care Provider. On March 21, he developed a cough, fever and body aches. At that time he tested positive and improved over 10 days.
After more than a month, he was re-exposed when someone in his household developed COVID-19. This time he developed worse symptoms, including an abnormal chest x-ray and low oxygen levels.
He tested positive again for COVID-19. Samples of virus from the first and second infection had differences suggesting reinfection.
At this point reinfections do not appear to be common, but they raise questions about how much immunity is actually produced with an infection -- or whether something else could be the cause -- like a bigger second exposure causing infection.