WHO: H1N1 vaccine safety akin to seasonal counterpart

Nov 19, 2009 (CIDRAP News) – Early experiences with pandemic vaccines in several countries suggest they have a similar safety profile to seasonal flu vaccines, an official from the World Health Organization (WHO) said today.

Dr Marie-Paule Kieny, director of the WHO Initiative for Vaccine Research, told reporters at a press briefing today that immunization campaigns are now under way in 40 countries and that national authorities from several of them are  tracking vaccine safety and regularly sharing their findings with the WHO.

Reports from these countries suggest one possible adverse event per 10,000 doses, of which 5 of 100 were classified as serious events and are being investigated by country health officials, she said. A small number of deaths following vaccine administration have been reported. Some are still being investigated, while others have ruled out the vaccine as the cause of death.

Kieny said the WHO has received fewer than 12 reports of suspected cases of Guillain-Barre syndrome (GBS), a rare side effect of the flu and other infections that was linked to a swine flu vaccine used by the United States in 1976. A WHO report on vaccine safety released today says GBS cases related to the H1N1 vaccine are fewer than 10.

"Only a few [GBS cases] may be linked to the [pandemic H1N1] vaccine. The illnesses have been transient, and patients have recovered," Kieny added.

More typical reactions are local redness and muscle pain that resolve in a day or two, she said. Various allergic reactions have also been reported. The WHO has received reports on all of the different vaccine forms: adjuvanted, unadjuvanted, and live attenuated influenza vaccine (LAIV), which is the nasal-spray version. So far the WHO has not detected any safety profile differences among the various vaccine types, she said.

"Vaccination campaigns continue worldwide, and the WHO will remain in close contact. The pandemic vaccine is as safe as the seasonal flu vaccine," Kieny said. "We hope the safety information will dissipate worries over the vaccine."

At least 80 million doses of pandemic vaccine have been distributed, and, according to information from 16 countries, at least 65 million doses have been administered.

Donated vaccine shipments to developing countries will start at the end of November and are slated to continue well into 2010, Kieny said. The WHO will try to provide only one type of vaccine for each country to streamline the logistics of handling the doses.

See also:

Nov 19 WHO pandemic briefing note: "Safety of pandemic vaccines"

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