Can You get COVID-19 Twice?

Over the past few months, as coronavirus has continued to plague the globe, several social media posts have appeared from people claiming to have had the virus twice. Scientists have been skeptical about this being a possibility, and there has been a lack of evidence supporting these claims.

However, new research suggests that those posts may have had some truth in them, after all. 

Can You Get COVID-19 Twice?

According to new research: yes you can. The proof for this seems to lie in the story of a 33-year-old man in Hong Kong who was first struck down with COVID-19 in March. The man tested positive after complaining of a cough, sore throat, fever, and headache, and he was quarantined in hospital until he tested negative twice.

Then, in mid-August, the same man returned to Hong Kong after visiting Spain and the UK. Both European nations are still seeing high numbers of infection and the man was screened at Hong Kong airport using a procedure that tests the saliva for the virus. Despite having no symptoms, the man tested positive and was taken to the hospital for monitoring. 

A New Mutation

While he was in the hospital, the patient’s medical team noted that his viral load (the amount of virus he had in his body) reduced over time, which suggests that the patient’s immune system was taking care of the infection on its own.

As we’ve previously reported, scientists know that COVID-19 is mutating, and this case is a perfect example of that. Both times that the man was hospitalized, doctors sequenced the genome of the virus that he was infected with. It was observed that the virus had changed in the four months between his first and second infections. The different sequencing of the virus and the time between infections is clear evidence that we can, in fact, be infected with COVID-19 twice. 

Herd Immunity and Vaccines

The WHO responded to Hong Kong’s case by saying that it seems people are developing an immune response that allows them to fight off the virus on their own. What is unclear, though, is how strong that response is, and how long it can last. Scientists are also unsure how often this is happening so we can’t be sure whether this is a rare case or a common occurrence, and more studies are needed to determine this. 

While new studies are being conducted, the research community is looking at the important implications that this development has on potential vaccines and the concept of herd immunity, which is when a large part of the population is immune to a disease.

Should We be Worried?

Although studies are in their early stages, it seems that reinfection is possible and those who have a weak immune response to the virus the first time they’re infected could be at a higher risk of contracting COVID-19 for a second time. This seems to be the case for the man in Hong Kong as doctors couldn’t find antibodies in his blood, which suggests that he had a weak immune response to his first infection in March. The positive news is that this patient quickly developed more antibodies during his second infection which suggests that it boosted his immune system. This is likely why he didn’t have any symptoms the second time.

Although the possibility of being reinfected is unnerving, experts say that there’s no need to panic about getting COVID-19 twice. This is actually a fairly normal occurrence that is seen in other kinds of coronaviruses including the ones that cause the common cold. That’s why most of us catch more than one cold in our lifetime: the virus mutates and we catch a new strain. The same mutation also happens with the seasonal flu, which is the reason that at-risk people have the flu vaccine.  

What Does This Mean For Us?

The good news from this development is that our bodies can get better at fighting COVID-19. However, there are some implications to consider. Regarding vaccines, one issue is that booster doses may be required to keep up with the developing virus. It also suggests that immune-based therapies might not work because the virus could outsmart the treatments. This includes therapies such as using plasma to obtain a concentrated dose of antibodies from people who have recovered from COVID-19.

As evidence grows that suggests instances of asymptomatic reinfection, we must remain vigilant and take care to protect ourselves and those in our communities. Wearing a mask is as important as ever in reducing the rate of transmission, and proper hygiene and social distancing should continue to be practiced.