Doctors have revealed that people may be able to catch Covid-19 twice, and suffer from its symptoms in completely separate infections of the virus within just four months.
In a case report written by Dr Jessica Tuan, Dr Anne Spichler-Mofarrah and Dr Oneyema Ogbuagu for the British Medical Journal (BMJ), the authors state that “cases of reinfection have been identified and mounting evidence shows that protective immunity after a first episode of infection may be short lived”.
The authors explain that there is currently “limited data” in regards to Covid-19 reinfection, as reported cases are “very few”.
The experts also say that it is unknown whether the case reports represent a genuine reinfection, or if it is actually continued viral shedding from the initial bout of the virus.
‘Reinfection is possible’
The authors of the study, which has been peer-reviewed, say: “As the Covid-19 pandemic has evolved, emerging reports have shown that SARS-CoV-2 reinfection is possible, such that positive SARS-CoV-2 RNA testing over a long period of time does not necessarily indicate persistent viral shedding from prior Covid-19 infection.
“If patients with severe disease develop more robust antibody levels, their duration of protection against reinfection and resulting severity of disease, if it does occur, may be muted.
“Future observations would certainly shed more light on this if this hypothesis holds true.
“The role of the presence or absence of antibodies after initial infection in survivors of a first episode of Covid-19 and its role in mitigating the risk of SARS-CoV-2 reinfection is not clearly defined.
“It is plausible, however, that waning immunity or absence of antibodies after the first episode of SARS CoV-2 infection may make one more susceptible to reinfection.”
The case study
The case study in the report showcased a 43 year old man with a past medical history of well-controlled type two diabetes, hypothyroidism and class three obesity.
He had initially been diagnosed with Covid-19 in April 2020 and had been hospitalised. This hospital stay had been complicated by “chronic respiratory failure for which he had a tracheostomy placed”.
Three months after his initial positive test, the man produced four interval negative SARS-CoV-2 RNA tests.
In early August 2020, he was admitted to hospital again, and tested positive for Covid-19. He stayed in hospital for just one day, but was readmitted to hospital again two weeks later, and was kept for a week.
‘We know that Covid-19 reinfections can happen’
Ashleigh Tuite, assistant professor at the University of Toronto’s Dalla Lana School of Public Health said: “We know that reinfections with [Covid-19] can happen.
“The bigger question is: if reinfections are going to happen, how frequently are they happening?”
Speaking to Sky News, Danny Altmann, professor of immunology at Imperial College London, said that while there are only 100 proven cases worldwide of reinfection, his discussions with doctors suggest that it is “far more common that we’ve imagined”.
He said: “Reinfection can happen a fair bit.”