VOA常速英语:Helper Serum Boosts Effectiveness of Flu Vaccine

Vaccines against swine and avian flu can be made more effective by the addition of a helper serum known as an adjuvant.  The finding from a new study could let vaccine makers stretch supplies and possibly lower costs when new influenza strains emerge.

Influenza vaccines are generally effective against a particular strain of the flu. But microbiologist Hana Golding of the U.S Food and Drug Administration says sometimes a new strain emerges suddenly, and there is a scramble to design and manufacture a new vaccine.

"And you want to really, very quickly, vaccinate the population, you need all the help you can get,"  she says.

Vaccines are based on an antigen - the ingredient that actually stimulates the body's immune response - plus other components.

A new study looked at the effectiveness of one of those other components - an adjuvant called MF59 - in boosting some flu vaccines.

"The MF59 is a class of adjuvant that is called oil-in-water emulsion, which is exactly what it says," Golding says. "This type of adjuvant works by attracting to the site of vaccination competent immune cells, whereby they're creating a local environment to facilitate the immune response."

In a study published in the journal Science Translational Medicine, Golding and her colleagues showed that adding MF59 to vaccines for H1N1 swine flu and for avian flu increased the immune response in various age groups.

One advantage of adding an adjuvant to a vaccine is that it may produce an equally effective dose using less antigen - the key ingredient that may be scarce or expensive in an emerging pandemic.

"If you have more efficient processing of a certain amount of vaccine, you don't need as much to get the same level of immune response. And if you can use less amount of vaccine per dose, then you can clearly have a much larger coverage."