BY OUR PHARMA CORRESPONDENT
8 August, 2005: Researcher of the National Institute of Allergy and Infectious Diseases in the United States claim that a vaccine developed against avian influenza could be useful in humans.
The vaccine is yet to undergo preliminary tests in humans, still the government researchers expressed the optimism that it can be used on an emergency basis if a pandemic developed.
Additional tests are needed to determine the number of vaccine shots required for protection, optimal dose of vaccine; and whether adding another ingredient to the vaccine could raise the potency of lower doses. Even when these tests are completed, more time will be needed before the Food and Drug Administration can license the human vaccine.
The National Institute of Allergy and Infectious Diseases scientists said that tests so far had shown that the new vaccine produced a strong immune response among the small group of healthy adults under age 65 who volunteered to receive it, although the doses needed were higher than in the standard influenza vaccine offered each year. The vaccine, developed with genetic engineering techniques, is intended to protect against infection, not to treat those who are sick.
Further tests are expected to be conducted among two groups - people 65 and older, and children - over the next several months.
However, they maintained that mass production of such a vaccine could well pose problems because the vaccine is made in chicken eggs. It all depends upon the number of eggs farmers can supply manufacturers. If manufacturers can overcome such hurdles, the new vaccine could go far in averting a possible pandemic of human influenza.
Health experts world over have been trying to develop a vaccine against the diseases because they a fear a pandemic as a strain of avian influenza is spreading in birds through Asia and Russia. Tens of millions of birds have died from the infection. Nearly 100 people have been infected, and about 50 have died from this strain of the avian influenza virus, called A(H5N1).
Earlier, a human vaccine against the A(H5N1) avian influenza virus was prepared after it first appeared in the world, in Hong Kong in 1997. That vaccine was never fully developed or used, and the strain has mutated since then.
So far, only a small number of human cases of A(H5N1) influenza have been found. Although a few cases may have been transmitted from person to person in Asia, the A(H5N1) strain has not garnered enough strength to spread widely among humans anywhere.
According to the World Health Organization in Geneva, the avian strain has killed 57 of the 112 people it has been known to infect in four countries. They are Cambodia (4 cases), Indonesia (one case), Thailand (17 cases) and Vietnam (90 cases).
The United States is thought to be the only country that has produced a human vaccine against the A(H5N1) influenza strain. Australia, Canada, France and Japan are among countries where scientists are trying to develop an effective vaccine.
Government researchers in the US developed the vaccine, which is produced by Sanofi-Pasteur, a French vaccine company that is now part of Aventis.
BY OUR PHARMA CORRESPONDENT