Professor Ivan Hung Fan-ngai of The University of Hong Kong recommends that older adults consider a recombinant influenza vaccine. He says it can provide protection for about a year, compared with about six months for an ordinary inactivated vaccine.
Hung said the longer protection could cover a June-to-August flu peak before the ordinary vaccine arrives in September.
He said the recombinant vaccine was suitable for people aged 65 or older and those with chronic illnesses, including cardiovascular or lung disease, diabetes and kidney disease. He also included people with suppressed immunity and cancer patients receiving chemotherapy or immunotherapy.
He said last summer’s and winter’s influenza peaks overlapped, increasing the risk of infection and complications for older people and those with chronic illnesses.
For people with cardiovascular disease, Hung said the risk of acute myocardial infarction could rise six to 17 times within a week of an influenza diagnosis, while the risk of stroke could increase about eight to 10 times. Separately, he said an influenza-triggered heart attack could raise the mortality rate 17-fold.
Hung said even a mild influenza infection could raise blood sugar in people with diabetes in the short term. He also said their risk of death from influenza complications was six times higher.
For people with cancer, he said, the risk of hospitalisation for severe influenza was three to five times that of the general population. After admission, their risk of death from complications could be up to 10 times higher.