"The influenza vaccine will not last until the next influenza season, since the immune defense of a person after vaccination decreases over time," - quoted by RIA Novosti WHO.
The organization noted that vaccination is required annually for optimal protection against circulating influenza viruses.
The WHO Global Influenza Surveillance and Response System (GISRS) continuously monitors influenza viruses and updates vaccine formulations twice a year.
Earlier it was reported that in Moscow about 900 thousand people were vaccinated against the flu at the workplace.