Spokesman Iain Simpson said the U.N. health agency had heard the U.S. Centers for Disease Control were looking into the possibility of a vaccine shortage in the United States.
"But as far as we're aware globally, no there's no shortage," said Simpson.
Health authorities in different parts of the United States said they were running out of flu vaccine after demand soared
because of reports that this year's epidemic was having a heavier impact than usual.
Shortages have also been reported in Singapore.
Simpson said WHO monitors the annual flu season, including availability of vaccine, through a network of health professionals
who report outbreaks and other developments.
"It's basically set up to identify the type of the virus that's circulating this year," said Simpson. "But it also acts as a clearing house for other information including information on vaccines, so if there were a vaccine shortage, then we would find out about it like that."
Simpson said there might be a shortage at one doctor's clinic or at one hospital, but government authorities would have to declare that there's a shortage in an entire country to raise the level of concern.
"Obviously if it's a shortage in a region, then it's about distribution within the country," he said. "If it's a shortage in a country, then WHO might get involved, but not necessarily."
Simpson said that shortages typically appear much later in the season, in February or March.
"Frankly by then flu vaccine is less worthwhile anyway because it takes several weeks to have its full effect," he said. "We recommend that people get vaccinated before or at the very beginning of the flu season.
"Vaccine does tend to run out at the end of the flu season, 구미출장마사지
and that's not a cause for concern. If vaccine were running out at this point, then it might be. It would depend on the circumstances in a particular country."