Flu patients may be able to fight the virus on their own, with a little help from an immunity booster that scientists around the world are researching.
It's a promising trend in infectious disease control - medication that helps the immune system fight viruses, instead of traditional drugs that kill viruses directly.
The medication seeks to harness the potential of the body's natural defence mechanism, particularly in treating severe respiratory viral infections.
Immune responses kick in when a protein called toll-like receptors (TLRs) detects foreign bodies invading body cells. So, medications that activate TLRs are expected to target different infections at the same time while not encountering problems in drug resistance.
At Chinese University, researchers say they have confirmed in patients of influenza A that TLRs trigger immune responses to suppress viruses.
The more the receptors were activated, the lower the viral count in patients, they said.
"The trend is promising. It works not by fighting infections directly but by boosting the immune system," Professor Nelson Lee Lai-shun, who led the study, said as their report was published this week.
Flu vaccines that stimulate TLR activity are undergoing clinical trials overseas. Such drugs had been tested in mice to fight viruses H1, H3 and H5, including bird flu, said Lee, head of the university's infectious diseases division. Other animal tests have shown the method's effectiveness in combating the virus of severe acute respiratory syndrome.
Lee believes TLR therapy will have advantages over traditional treatments. "It covers a wide spectrum, unlike anti-viral drugs, which target the virus and fail to work when the virus mutates slightly," he said.
Lee worked with his colleague in chemical pathology, Professor Wong Chun-kwok, to examine 42 patients who had H3N2 or H1N1.
In Hong Kong, infectious diseases have been a research focus in the post-Sars years. Lee's team has discovered the importance of using anti-viral drugs early in flu treatment and found steroids will worsen patients' conditions.