A Nevada man is thought to be the first person in the US to be infected twice by the coronavirus, with the second infection being worse than the first.
The 25-year-old essential worker from Reno, Nevada, first experienced a sore throat, cough, headache, nausea and diarrhoea, and was tested positive for Covid-19 on April 18.
After treatment, he tested negative for the virus twice in May. Then on May 31, he presented with the same symptoms, in addition to a fever and dizziness. He tested positive for Covid-19 a second time.
Another test revealed he had developed antibodies against the first infection. A genetic analysis of the second virus revealed slight differences to the first, causing speculation that his antibodies did not recognise it.
Dr Mark Pandori, director of the Nevada State Public Health Laboratory, said in a statement that the fact that a person was reinfected “on such a short timeline indicates there may be implications for the efficacy of vaccines developed to fight the disease”.
On Monday, researchers revealed a 33-year-old Hong Kong man was the first person ever confirmed to be reinfected with the coronavirus. It also emerged this week that two other coronavirus patients, one from the Netherlands and one from Belgium were reinfected.
It is known that respiratory infections like Covid-19 do not provide lifelong immunity like, for example, a measles infection does.
Pandori said the lesson to be learned is that even people who have been sick with Covid-19 need to protect themselves by wearing a mask, avoiding large gatherings, washing hands frequently and maintaining social distance.
“You’re not invulnerable to this,” Pandori said. “In fact, you could get it worse the second time.”