Japan's health ministry research team is calling on continuing protective measures against coronavirus even after people are vaccinated. The call follows a report that a recipient of the Pfizer-BioNTech vaccine subsequently contracted the virus.
The team says they learned that a medical worker in her 20s tested positive and was admitted to hospital after she received her first dose in late February.
The researchers say the illness report came six days after the vaccination and the recipient was likely infected with the virus after receiving the shot. They added that her condition improved and she has been discharged from hospital.
The team is tracking the health condition of about 19,000 healthcare workers in Japan who were vaccinated. It says this was the first case of coronavirus infection confirmed after workers received a vaccination.
The researchers say it is presumed to take about 14 days for a first-dose recipient of the Pfizer-BioNTech vaccine to develop a certain level of immunity.
The US Centers for Disease Control and Prevention said in March that even people who are fully vaccinated have a slight chance of getting infected and transmitting the virus to others. It said they still need to take preventive measures, such as wearing face masks in public places.