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Study says coronavirus immunity might only last 6 months

Published May 26th, 2020 9:54AM EDT
Coronavirus Immunity
Image: Ajay Aggarwal/Hindustan Times/Shutterstock

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  • Coronavirus immunity might last as little as 6 months and as long as 12 months, a new study from Europe indicates.
  • The conclusion is based on statistical data from a study that looked at human immunity against four coronaviruses that are responsible for the common cold.
  • Determining the actual duration of COVID-19 immunity is a crucial detail for vaccination campaigns, concepts like herd immunity and “immunity passports,” as well as other official protocols meant to reduce the spread of the disease until treatment is widely available.

The world has come a long way in around 5 months of fighting a virus that had never challenged humans before. SARS-CoV-2 is the newest member of a coronavirus family that we’ve already trained ourselves to fight. Four other versions cause common colds, and the SARS and MERS coronaviruses were responsible for dangerous outbreaks in the past two decades. The novel strain is the most dangerous of them all considering what happened so far. More than 5.6 million people have been infected as of Tuesday morning, and over 351,000 people lost their lives so far. That’s a huge sacrifice the world had to make, but it wasn’t all in vain. The strict social distancing measures that most countries implemented have saved lives, stopped the spread of the novel coronavirus, and bought us all precious time. Doctors treating the disease and researchers were able to come up with viable therapies that helped save lives. More courses of treatment for COVID-19 are in testing, as well as brand new drugs that have been explicitly designed to boost the immune response against the novel virus. Separately, more than 100 drug makers are developing vaccine candidates, and several of them proved their worth in pre-clinical and clinical tests. It seems like it’s just a matter of time until the first viable vaccine is ready for mass inoculation.

But it’s at this point that we have to take into account one of the worst types of outcomes going forward. Vaccines should be effective or safe against COVID-19, but there’s a possibility that coronavirus immunity might be shored-lived, regardless of whether it’s obtained by surviving the disease or via immunization. Now, a new study tells us that might indeed be a possibility for SARS-CoV-2, and immunity might last as little as 6 months.

Experts including Dr. Anthoni Fauci and scientists at the World Health Organization (WHO) warned that it’s unlikely the novel coronavirus can be eradicated and that COVID-19 might never go away. That’s certainly not a problem if vaccines and drugs work. The flu was never eradicated either, but we learned to live with it and beat it.

We’re yet to get to a point where COVID-19 treatment is available over the counter, and there can’t be talk of herd immunity without extensive loss of life. More than 60% of people from a community would need to get the virus to reduce transmission risks for the others. We could also get there via vaccination, but only assuming immunity lasts long enough for at least 60% of the population to be protected at all times.

Researchers from the Netherlands think that novel coronavirus antibodies might not provide long-lasting immunity if this new virus behaves like the other four coronaviruses that cause common colds. A brand new study (via Euronews) says that protection could last as little as 6 months and up to 12 months for the other coronaviruses.

The researchers looked at medical records for 10 men over 35 years to determine antibody levels for any of the four seasonal human coronaviruses. The men were tested at 3 or 6 months, and the researchers discovered an “alarmingly short duration of protective immunity to coronaviruses.”

“Frequent reinfections at 12 months post-infection and substantial reduction in antibody levels as soon as 6 months post-infection” were observed for those viruses. If the novel coronavirus behaves the same way, then talk of “immunity passports” and herd immunization is pointless. A person who recovered from COVID-19 could get it again in 6 to 12 months without another vaccine shot — again, that’s if beating a SARS-CoV-2 infection provides limited immunity, as is the case with its siblings. This is likely, but it hasn’t yet been proven.

The researchers note that the human coronaviruses are “biologically dissimilar” and “have little in common, apart from causing the common cold.” But SARS-CoV-2 doesn’t have to be similar to any of them to follow the same immunity pattern.

Previous reports detailing so-called immunity passports noted that one of the main problems with this sort of endeavor is that we have no idea how long COVID-19 immunity lasts. Scientists looking at the matter and comparing COVID-19 with SARS and MERS think that protection could last between 1 and 8 years, according to The New York Times. But COVID-19 hasn’t been with us for long enough to test any of that. Other researchers also warned that coronavirus immunity might not be that great in general, suggesting that vaccine-induced resistance might be better than surviving the disease.

What we do know for sure at this point in time is that COVID-19 patients who recover can be reinfected soon after they’ve been cured. Those “reinfection” cases reported around the world are not relapses, researchers from Korea’s CDC were able to prove recently. The coming months will provide more COVID-19 immunity data.

This new study might seem like bad news, but it isn’t necessarily that bad. Regardless of how long the immunity lasts, if this virus can’t be eradicated, we’ll still have to learn to live with it. Drugs, therapy protocols, and vaccines could help us manage COVID-19 much better, however.

Also, the study does have a few limitations and more research is required to confirm its findings. The researchers note that the cohort includes only men and that they were not able to sequence the virus genome during infection, factors that could influence their findings. Also, there’s no indication that SARS-CoV-2 necessarily behaves like the other coronaviruses.

Separately, other researches observed strong immune responses in some COVID-19 patients, theorizing that past infections with one of the milder human coronaviruses that preceded COVID-19 might be responsible for the strong immune reaction. Those findings are yet to be confirmed but if they’re proven to be correct, then the other four coronaviruses that will continue to circulate could provide some sort of immune protection against COVID-19.

Strangely enough, the Dutch study does say that three of the 10 men who were studied for decades carried antibodies that recognized the SARS-CoV-2 N protein as early as 1985, but also in 1992 and 2006. Of course, COVID-19 didn’t exist at the time.

Chris Smith Senior Writer

Chris Smith has been covering consumer electronics ever since the iPhone revolutionized the industry in 2008. When he’s not writing about the most recent tech news for BGR, he brings his entertainment expertise to Marvel’s Cinematic Universe and other blockbuster franchises.

Outside of work, you’ll catch him streaming almost every new movie and TV show release as soon as it's available.