Mon Feb 23, 2009 5:00pm EST
LONDON, Feb 23 (Reuters) – Scientists at Swiss drugmaker Novartis (NOVN.VX) have found a faster way to test H5N1 bird flu vaccines in people, in a move that should speed preparations for mass immunisation in the event of a global pandemic.
Manufacturers hunting for the best vaccines to stop the disease face a race against the clock if the H5N1 strain of influenza now circulating in birds mutates and starts spreading easily among humans, as many researchers fear.
Current clinical testing methods frequently take a year or more to measure a person’s immune response. By contrast, the new technique should be able to predict after a single dose whether a vaccine offers protection.
Rino Rappuoli and colleagues, writing in the Proceedings of the National Academy of Sciences on Monday, said their work could lead to a quicker way of identifying and producing the correct vaccine for use at the start of any pandemic.
They tested two vaccines in a Phase II study, one made with flu antigens alone and one with an extra adjuvant, or additive, to make the antigens easier for the immune system to detect.
The adjuvanted vaccine produced a much stronger response and the researchers found that a three-fold increase in the number of so-called memory T cells was a strong predictor of whether people were properly immunised six months later.
By measuring this response, vaccine developers should have a much faster way to assess the effectiveness of future vaccines, they concluded. The finding is the second piece of good news in two days in the fight against the risk of bird flu, following the discovery of human antibodies that can neutralise H5N1 bird flu and other strains of influenza.