Seven of the 22,000 medical workers vaccinated against H1N1 swine flu have developed side effects, the Health, Labor and Welfare Ministry said.
The finding, released Friday, was revealed after a four-day survey was completed Thursday to ensure the new vaccine was working on doctors and nurses at 67 designated hospitals run by the National Hospital Organization.
Four of the seven developed serious side effects, including vomiting and diminished consciousness, but all are recovering, the ministry said. The other three complained of minor symptoms, such as developing hives.
Meanwhile, other hospitals reported that 25 patients were exhibiting adverse effects from the new vaccine, including two serious cases.
The ministry said half of the 32 people who developed symptoms were found to have food and drug allergies or allergic asthma.
The survey will be followed by large-scale vaccinations of the general public in November, with priority given to people at high risk of developing complications from the flu.