The ongoing coronavirus pandemic has infected almost 36 million people worldwide – and affected countless others. As the race to find a vaccine against the virus continues, health experts are worried there might be a new curve ball in the equation.
Health experts have noted that one way the virus can be stopped in its tracks is when herd immunity occurs – this is when enough people (around 60% or 70% of the population) develop an immune response, either through previous infection or vaccination. If the virus can’t find susceptible hosts to infect, it won’t be able to spread easily. This is the ultimate goal of a vaccine. But with so much unknown about SARS-CoV-2, scientists continue to discover new findings about the virus.
However, a growing number of confirmed cases of COVID-19 re-infections is raising concern. The first case of re-infection was confirmed in Hong Kong in August, but was soon followed by more from other countries including the US, the Netherlands, Ecuador and India.
According to CDC guidelines, “based on the latest science about COVID-19 showing that people can continue to test positive for up to 3 months after diagnosis and not be infectious to others.”
Although it’s entirely possible that the second positive test can be from the initial infection, or could be an effect similar to families of viruses that can go dormant and then reactivate – think chicken pox, which can re-occur in another form, like shingles – scientists have come up with a method to confirm actual re-infection, it just takes a more thorough testing. Both sets of swabs are examined for the genetic code of the virus from each occurrence of the illness and compared to prove that they are distinct.
In the US, scientists from the University of Nevada at Reno and the Nevada State Public Health Laboratory reported the first case of coronavirus reinfection later in August – a 25-year-old man tested positive for coronavirus twice, each time from distinctly different coronavirus infections.
One study released in July showed that antibodies generated by COVID-19 survivors may begin to fade just 20 to 30 days after the symptoms first appear.
Shiv Pillai, an immunologist at the Ragon Institute of Massachusetts general hospital, did a study on whether COVID-19 patients can generate highly effective, long-lasting antibodies that would fight the virus for years. However, his findings suggest that the patients were unable to do so.
“If we want antibodies that will persist for a few years and protect us, it’s not clear that’s going to happen,” he said.
But he remains hopeful about the vaccines. “I don’t see why the vaccines won’t work. They may not be fantastic, but I believe that’s what’s going to protect us,” he said.
