'Universal' flu shot just five years away?

WASHINGTON, July 27 (UPI) -- A universal flu vaccine against all strains may come in the next five years, replacing annual shots, the chief of the National Institutes of Health said.

Dr. Francis Collins said Tuesday he is "guardedly optimistic" about the possibility of a long-term inoculation to replace the one "you'd have to renew every year," USA Today reported.

A universal vaccine "seemed completely out of reach only a few years ago," Collins said, because flu viruses mutate yearly, quickly rendering each year's vaccines developed for specific flu viruses obsolete.

However, researchers have discovered "there are parts [of the virus] that don't change …. If you designed a vaccine to go after the constant part of the virus, you'd be protected against all strains," Collins said.

Such a vaccine is "not a question of whether, but when," Arnold Monto of the University of Michigan said. "I think five years is a bit ambitious, given where we are now."

In February, researchers in the United Kingdom announced some preliminary success in creating a universal flu vaccine for humans, USA Today reported.