Health Care Workers Can Get COVID Twice (at Least)

As the coronavirus disease 2019 (COVID-19) pandemic continues to rage uncontrollably, the need for infection preventionists and other healthcare professionals to man the frontlines against the novel coronavirus (with daunting layers of complexity still being discovered) grows every day. They’re exhausted from holding off a disease for more than a year that now reaches unprecedented levels every 24 hours; caught in a cycle in which each day is worse than the day before.

When a health care professional is infected by SARS-CoV-2, if the symptoms are manageable, they’re quarantined for 7 or 10 or 14 days, as the US Centers for Disease Control and Prevention adjusts guidelines. Then many of those professionals—they’ve been called “heroes” with good reason—get right back into the battle. Because they’ve already gotten the disease, they’re now immune. But for how long?

About five months for about 17% of those workers, says a study by Public Health England (PHE) of about 20,000 health care workers in Great Britain. “The study found that antibody protection after infection lasts for at least 5 months, on average, and scientists are currently studying whether protection may last for longer,” PHE said in a press release. “This means that many people who contracted the disease in the first wave may now be vulnerable to catching it again.”

The PHE’s SIREN (SARS-CoV-2 Immunity and Reinfection EvaluatioN) study examines data of health care workers collected from June 18 to November 24, 2020, and found 44 reinfections—2 classified as “probable” and 42 as “possible—among 6614 workers who’d tested positive for antibodies. That’s an 83% protection rate from being reinfected by COVID-19.

However, asymptomatic carriers continue to be a major cause of COVID-19 spread. And the fact that 83% of health care workers appear to be immune from reinfection after 5 months, those who work, live, or gather with them may not be so lucky. These findings represent only the first stage of the SIREN study.

The PHE press release says that “although those with antibodies have some protection from becoming ill with COVID-19 themselves, early evidence from the next stage of the study suggests that some of these individuals carry high levels of virus and could continue to transmit the virus to others.”

Just how much protection and for how long the COVID-19 vaccines provide were not part of the investigation. As is the case with nearly all expert advice about avoiding COVID-19 infection, the SIREN investigators emphasize that the so-called low-tech methods of infection prevention still need to be followed: hand hygiene, social distancing, masking.

“We now know that most of those who have had the virus, and developed antibodies, are protected from reinfection, but this is not total and we do not yet know how long protection lasts. Crucially, we believe people may still be able to pass the virus on,” PHE says in its press release. “This means even if you believe you already had the disease and are protected, you can be reassured it is highly unlikely you will develop severe infections but there is still a risk that you could acquire an infection and transmit to others. Now more than ever it is vital we all stay at home to protect our health service and save lives.”