What’s Up Doc?: Use of high-dose influenza vaccine for seniors
By Dr. Noorali Bharwani on September 29, 2020.
Our immune system changes as we get older. And flu season takes its toll. Use of high-dose influenza vaccine for people 65-years of age and older can have some benefits. Canada’s flu season typically starts in October, when temperatures drop and people are in closer contact with each other indoors. The time to get a flu shot is between now and November, before the virus is circulating widely, says the Public Health Agency of Canada (PHAC) on its website. As Canada braces for another flu season alongside COVID-19, experts say it’s difficult to predict the severity of the virus and the effectiveness of the flu shot this year. How many Canadians are affected by the flu each year? An estimated 3,500 Canadians die of the flu each year and 12,200 are hospitalized, making it one of the 10 leading causes of death in this country, says PHAC. According to the national Influenza Vaccine Coverage Survey, we know that only 42 per cent of Canadian adults reported getting the flu shot last season, though it’s up from 38 per cent in the 2017-18 season and 36 per cent in 2016-17. “Despite the fact that the influenza vaccine is much better than nothing … a lot of people still think that they don’t want to get it because it’s not good enough,” says Dr. Allison McGeer, a physician and infectious diseases specialist at Mount Sinai Hospital in Toronto (Second Opinion CBC Oct 12, 2019). “Influenza vaccines are about 50 or 60 per cent effective in protecting you from hospitalization due to influenza. How good are seat belts at protecting you from dying in a car accident? About 50 per cent. How good are smoke detectors at reducing your risk of death in a house fire? About 35 per cent. So, we have this weird double standard that goes on with vaccines,” says Dr. McGeer. There are two types of flu vaccines. The high-dose vaccines contain four times as much flu virus antigen – the part of the vaccine that stimulates the immune system – as regular Fluzone and other standard flu vaccines. High-dose vaccines are meant for seniors. This can give older people a higher immune system response against the flu. Fluzone High-Dose is approved for use in Canada for adults 65 years of age and older. It costs about $75 and needs to be ordered in advance compared to regular Fluzone vaccine. There is no charge for the regular vaccine. Fluzone High-Dose is given by injection. Like other flu vaccines, Fluzone High-Dose is made up of the three flu strains most likely to cause the flu during the upcoming flu season. A new vaccine called Fluzone High-Dose Quadrivalent that is made up of four flu strains has also been approved for people age 65 and older. People age 65 and older have the highest risks of flu complications. Protecting this group from the flu is especially important. Some older adults may have weaker immune systems, which can lead them to be less protected after a regular flu vaccine. In response to a regular flu shot, older people produce 50 per cent to 75 per cent fewer antibodies, which protect against the vaccine antigens, than do younger adults. Studies have found higher antibody levels in older adults who received high-dose flu vaccines than in those who received standard flu vaccines. In addition, one study found almost 25 per cent fewer cases of influenza in adults age 65 and older who took the high-dose vaccine compared with those who took the standard-dose vaccine. In a large study comparing high-dose and standard-dose flu vaccines, those who received the high-dose vaccine were more likely to develop side effects during the week after getting the vaccine. Side effects included a fever and soreness at the injection site. Canada’s National Advisory Committee on Immunization (NACI) concluded that Fluzone High-Dose vaccine for older adults should provide superior protection compared with our standard dose vaccine. It is 24.2 per cent more effective than regular Fluzone vaccine. We are going to face many challenges this winter. So, make sure you get your flu shot as soon as it is available. Take care. Be safe. Protect yourself and protect others. Dr. Bharwani is a general surgeon, freelance writer, photographer and author of A Doctor’s Journey and Doctor B’s Eight Steps to Wellness. His latest book is available at Shoppers Drug (Medicine Hat Mall), and http://www.nbharwani.com. You can discuss this article and other articles on his website: nbharwani.com and sign up for RSS feed, Twitter or get on the email list. 20-19
