Japan on Tuesday began coronavirus vaccinations for children aged six months to four years at a hospital in Tokyo, expanding the eligibility criteria for inoculation to almost all age groups.
Vaccinations for babies and young children in other areas of the country are set to follow as soon as local governments are ready, since deliveries of the vaccine began the previous day.
Children will be required to have a total of three doses of the vaccine, which targets the original strain discovered in Wuhan, China, in 2019, in order to achieve a similar level of immunity as those in other age groups.
The first and second shots must be administered three weeks apart, while the third inoculation will be given at least eight weeks after the second shot.
Inoculation can be carried out at the same time as the influenza vaccine, but no other vaccines can be administered, in principle, for two weeks before and after vaccination.
Although the vaccine, produced by Pfizer Inc. and BioNTech SE, was not specifically developed to combat the highly contagious Omicron variant, clinical trials have shown the vaccine to be effective, with an efficacy of around 73 percent.
Clinical trials also found that 16 percent of children between 6 months and less than 2 years old reported arm pain, while 7 percent in the same age group experienced fever after inoculation.
Among children aged between 2 and 4 years, 27 percent experienced arm pain and 25 percent reported fatigue, but Japan's health ministry said most of the side effects were mild and there were no safety issues.
At a hospital in Tokyo's Minato Ward, 2-year-old Yui Iwami received the shot on the lap of her mother, Yumiko, who said she was concerned about the "eighth wave" of the coronavirus infections, which is thought likely to spread around the same time as the seasonal flu.
"I made sure my daughter received the shot to prevent her from getting seriously ill. I came on the first day because I was looking forward to getting her vaccinated," the 36-year-old mother said.
All of the 20 reservations for the shots on the day were filled, according to the local government.
Inoculation for younger children started after an increase in the number of children who died or suffered severe symptoms, as the spread of the Omicron variant led to a sharp rise in infections.
An academic report has shown that around 60 percent of children who developed moderate or severe symptoms due to infections since July were under the age of 5, according to the Ministry of Health, Labor and Welfare.