Can You Get Coronavirus Twice?

The COVID-19 pandemic has prompted many questions about the characteristics of the little-understood new coronavirus that caused it, including whether people can catch it twice.

Reports of COVID-19 patients testing positive on two occasions have emerged since the outbreak began in China late last year, including one regarding a Japanese tour bus guide. According to Reuters, similar incidents were previously documented in China.

Asked about the Japanese case at a coronavirus press conference earlier this week, the top scientific and medical advisers to the U.K. government said those who catch the new coronavirus will develop some immunity, it is rare for people to catch infectious diseases twice, and there is no evidence of this happens with the virus which causes COVID-19.

Speaking to Newsweek, experts said that they can't be certain, based on the limited data there is on SARS-CoV-2 (the germ which causes COVID-19 and shouldn't be confused with the Severe acute respiratory syndrome (SARS) virus). However, it would be very highly unlikely for a person to twice catch the bug.

Dr. Benjamin Linas, an expert in infectious diseases at Boston Medical Center and Boston University, told Newsweek: "This is a novel virus and we do not really know. There are very early reports of people being re-infected with COVID-SARS2, but they are case reports only.

"Perhaps there is something special or different about those individuals. Maybe they have immune system suppression, maybe they take medicines that somehow make them more susceptible to re-infection. We do not know yet."

It's important to remember, Linas went on, that "being 'immune' is not an all-or-nothing issue.

"For example, it may be true that people can be re-infected with SARS-CoV-2, but that the second time around the infection is less serious, because there is some partial immunity."

Dr. Keiji Fukuda, director and clinical professor at the University of Hong Kong School of Public Health, agreed that "there is little good evidence to show that a person with a normal immune system will get reinfected within months of having been infected."

He suggested to Newsweek: "There are other possible explanations why a person may seem to have gotten re-infected.

"The original illness may not have resolved; the test may be providing the wrong result; the specimen was not collected or handled correctly and was contaminated."

Ian Jones, professor of virology at the U.K.'s University of Reading, stressed to Newsweek the potential for reinfection "is a distraction as it is not the usual outcome."

He said: "The vast majority of people who recover will have immunity that will last many years if not a lifetime."

Fukuda said that while we don't know how long a person's immunity to the same strain of coronavirus will last, "reinfection within weeks is very, very unlikely."

Asked whether SARS-CoV-2 will become a disease like the flu which reappears seasonally and for which we need a new vaccine each year because of potential new strains and a person's waning immunity, the experts were split.

Fukuda said: "The SARS-CoV-2 virus is already beginning to divide into different lineages; this is not surprising given that it is an RNA virus. If it becomes an endemic infection that appears in a seasonal pattern, like influenza, then it is possible that vaccination will be needed each year, like influenza."

Donald Burke, professor of health science and policy at the University of Pittsburgh, told Newsweek he wasn't sure, but as SARS-CoV-2 has the same kind of error correction molecular machinery as the virus that causes SARS, "its mutation rate will be slower."

However, Jones said: "So far SARS-CoV-2 has not changed and there is no need to consider multiple vaccines. The focus should be on getting one as quickly as possible."

Asked how worried he was about the virus, Linas said he is most concerned by hospitals being overwhelmed by cases.

But Linas also tried to provide some hope. "I am also encouraged by several things. First, the level of scientific collaboration, globally, is inspirational. When we end this pandemic, it will shine as the greatest example of human ingenuity and scientific advancement in the history of humanity," he said.

Linas added: "Second, the growing spirit of social solidarity at the same time that we are physically distancing is one of the best demonstrations of what it is to be 'human' that I have experienced in my lifetime.

"No one has ever attempted a truly global scale effort toward social distancing and public health intervention—ever," said Linas. "I challenge anyone to think of another time that we—I mean the biggest we of all, humans—have engaged in a project together, at the same time, for our own protection? I think that we will emerge a stronger society with new priorities when this is over."

World Health Organization advice for avoiding spread of coronavirus disease (COVID-19)

Hygiene advice

  • Clean hands frequently with soap and water, or alcohol-based hand rub.
  • Wash hands after coughing or sneezing; when caring for the sick; before; during and after food preparation; before eating; after using the toilet; when hands are visibly dirty; and after handling animals or waste.
  • Maintain at least 1 meter (3 feet) distance from anyone who is coughing or sneezing.
  • Avoid touching your hands, nose and mouth. Do not spit in public.
  • Cover your mouth and nose with a tissue or bent elbow when coughing or sneezing. Discard the tissue immediately and clean your hands.

Medical advice

  • If you feel unwell (fever, cough, difficulty breathing) seek medical care early and call local health authorities in advance.
  • Stay up to date on COVID-19 developments issued by health authorities and follow their guidance.

Mask usage

  • Healthy individuals only need to wear a mask if taking care of a sick person.
  • Wear a mask if you are coughing or sneezing.
  • Masks are effective when used in combination with frequent hand cleaning.
  • Do not touch the mask while wearing it. Clean hands if you touch the mask.
  • Learn how to properly put on, remove and dispose of masks. Clean hands after disposing of mask.
  • Do not reuse single-use masks.
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People wear masks on their faces in the streets of the city center in Brussels, Belgium, on Wednesday 18 March 2020. THIERRY ROGE/BELGA MAG/AFP via Getty Images