Various researches in recent years have shed hope to achieve a universal flu vaccine that may life-long protect the human body against all strains of virus; a new study, however, claims that there are more hurdles to clear that what previous studies thought to produce the game-changing vaccine.
On August this year, after its successful trials with mice, ferrets and monkeys, independent studies claim it has achieved the "first promising step" to developing a better vaccine that will cover a pandemic virus.
What they have achieved, so far, is mimicking a tiny portion of the flu virus known as a hemagglutinin stem, the part of the virus that remains relatively unchanged. Observing the hemagglutinin stem helped scientists develop experimental vaccines that protected animals on trial from H5N1 avian flu and H1N1 swine flu.
A new study, however, suggests that the universal vaccine worked on for years by scientists may not produce their expected effect. Here's why: when hemagglutinin is seen by the immune system, it sends antibodies that generally targets and neutralizes the head of the hemagglutinin, the part which unlike the hemagglutinin stem, changes continuously to evade the immune system's defenses. The previous studies, accordingly, focus on the hemagglutinin stem because in theory, if the antibodies can target and neutralize the hemagglutinin stem, it can attack multiple strains of flu.
The new study published in this week's issue of Translational Medicine and reported in Stat News, however, pointed out that the human body does not produce a lot of antibodies that target the hemagglutinin stem. The study highlighted that when the virus is new, the antibodies would target both the head and the stem but through subsequent vaccinations, antibodies produced generally target the head only. And according to Paul Thomas, immunology expert and the new study's lead author, said that subsequent vaccinations produce antibodies that tend to impede the production of antibodies that target the hemagglutinin stem.
Thomas, therefore, suggested that claims of universal flu vaccine being within sight should not be taken heavily.
