A study by the University of Oxford finds that people who have had COVID-19 are highly unlikely to contract it again for at least six months after the first infection.

According to Reuters, these results published on the MedRxiv website are from a British study of healthcare workers on the frontline in the fight against coronavirus.

Researchers at Oxford studied healthcare workers for 30 weeks since April. They found that 89 of eleven-thousand-52 staff who did not have antibodies developed a new infection with symptoms, while none of the over 12-hundred staff who had antibodies developed a symptomatic infection.

Researchers said that staff with antibodies were also less likely to test positive for COVID-19 without symptoms, with 76 without antibodies testing positive, compared to only three with antibodies. They added the three were all well and did not develop symptoms.

David Eyre, a professor at Oxford who co-led the study said his team will continue to follow the same cohort of staff to see how long protection lasts and whether previous infection affects the severity of infection if people do get infected again.

Reuters said that senior World Health Organization officials have also welcomed the study’s findings and cited Mike Ryan, WHO’s top emergency expert, as saying that it shows sustained levels of immune response in humans and also gives us hope on the vaccine side. 

Maria van Kerkhove, the WHO’s technical lead on COVID-19, was meanwhile quoted as stressing the need to follow these individuals for a longer period of time to see how long immunity lasts.