COVID-19 rebound refers to the return of symptoms or a new positive test result after an individual has initially recovered from the illness. This phenomenon can cause confusion and concern, particularly regarding the potential for renewed contagiousness. Understanding the nature of COVID-19 rebound and the necessary precautions is important for public health.
Understanding COVID-19 Rebound
COVID-19 rebound involves a recurrence of symptoms or a new positive viral test result after initial recovery from the illness. This can happen after symptoms have subsided and a person may have even tested negative. While often discussed in the context of antiviral treatments like Paxlovid (nirmatrelvir/ritonavir), rebound can also occur in individuals who did not receive antiviral medication.
Researchers are still working to fully understand why rebound happens, but it is believed to be part of the natural course of the SARS-CoV-2 infection for some individuals. One hypothesis suggests that early antiviral treatment might suppress viral replication without completely clearing the virus, allowing residual virus to grow once the treatment concludes. Studies have shown that rebound can occur in a significant percentage of untreated individuals, with some reports indicating rates as high as 30% to 33%. Symptoms during rebound are mild, and there have been no reports of increased hospitalizations or deaths specifically due to rebound.
Contagiousness of Rebound COVID
Individuals experiencing COVID-19 rebound are considered contagious. A positive rapid antigen test during a rebound indicates the presence of enough viral material to be transmissible to others. This means that even if symptoms are mild or absent during rebound, the virus can still be shed.
The duration of contagiousness during rebound is similar to the initial infection. It lasts as long as symptoms are present and/or tests remain positive. A positive rapid antigen test, even with a faint line, indicates the virus is present and can be transmitted. For many, a positive rapid antigen test can persist for several days after symptom onset, with some studies showing about 80% of symptomatic individuals still testing positive five days into the Omicron period.
Precautions During Rebound
Precautions are important if you experience COVID-19 rebound. If symptoms return or you test positive again after initial recovery, you should restart isolation. The Centers for Disease Control and Prevention (CDC) recommends re-isolating for at least five days from the onset of rebound symptoms or the positive test result.
You can end this re-isolation period after five full days if your fever has resolved for at least 24 hours without the use of fever-reducing medication and your other symptoms are improving. Following isolation, it is advisable to wear a high-quality mask, such as an N95 or KN95, for an additional five days, or up to 10 days from the start of rebound symptoms, especially when around others. Avoiding contact with vulnerable individuals during this period is also recommended. If symptoms persist or worsen during rebound, contacting a healthcare provider for personalized advice is appropriate.