A person caught coronavirus twice – and the second time it was worse


The news: According to a study published in The Lancet Infectious Diseases, a man in the United States caught Covid-19 for the second time in just two months. This makes him the fifth person to officially catch the coronavirus twice after cases in Hong Kong, Belgium, Ecuador and the Netherlands (and there will certainly be more cases we don't know about). The strange thing about his case, however, is that the second time around he had a worse illness. His doctors compared the genome of the virus during the two diseases and found that they were too different to be caused by the same infection. There is only one other recorded case where this has happened – the case in Ecuador.

The details: The 25-year-old man tested positive for the first time on April 18 after having had symptoms such as sore throat, cough, headache, nausea and diarrhea for several weeks. He felt fully recovered by April 27, and tested negative for the virus on both May 9 and May 26. But just two days later, on May 28, he developed symptoms again, this time with fever and dizziness. He tested positive on June 5 and had to be hospitalized after his lungs couldn't get enough oxygen into his body, causing hypoxia and shortness of breath. He had no underlying health conditions. The man has now recovered.

The significance: A single infection does not mean that you are protected from re-infection, even if such cases are still rare. Only five of nearly 40 million confirmed cases worldwide have been identified. That means people with Covid-19 still need to stay vigilant, follow social distancing advice, wear face masks, and avoid crowded, poorly ventilated rooms. This wasn't entirely unexpected: Coronavirus experts warned us that other coronaviruses like the common cold are seasonal. However, there are still many questions that researchers need to answer. How much protection does Covid-19 offer? Is this mainly due to antibodies or T cells? How long does the protection last? What does this mean for the medical treatments that are being developed or for vaccines? For example, do we all need an annual shot instead of a one-time vaccine? Last but not least, this new case is a reminder of how much we do not yet know about this virus.


Steven Gregory