Harming the herd
Is vaccine complacency dashing Ottawa’s hopes at herd immunity?
As another Ottawa winter looms, promising bitter cold, icy roads and heavy snows, the city braces for a more microscopic threat.
For most, the flu is little more than a perennial nuisance; yet another reason to dread the coming of winter. But for some deemed at-risk for complications related to infection, such as pregnant women, young children and elderly people, the flu season poses a real danger.
“Protect yourself and others from the flu.”
This directive, posted on the Ottawa Public Health website, promotes mass immunization in the name of protecting society’s most vulnerable.
This is known as herd immunity, achieved when enough people are immunized to diminish the spread of disease throughout the population.
But is Ottawa really getting the message?
Ottawa Public Health data suggests that fewer people are getting the flu shot, a trend that might prove dangerous for at-risk populations. This departure from the objectives of herd immunity, along with province-wide delays in the delivery of the high-dose vaccine, may heighten the severity of the upcoming flu season, especially for the elderly.
In the 2017-18 flu season, just 34 per cent of adults aged 18 to 64 reported receiving the shot, 12 per cent less than the turnout five years ago.
The flu shot is often praised as our best defence against seasonal infection. So why aren’t more people getting vaccinated?
Anti-vax criticism
One theory links the decline in immunization rates to the growing influence of anti-vaccination ideology, which spreads misinformation about the dangers of vaccines online.
“Vaccine misinformation is a major threat to global health that could reverse decades of progress made in tackling preventable disease,” said the World Health Organization in a statement earlier this year. “Think measles, diphtheria, hepatitis, polio, cholera, yellow fever, [and] influenza.”
The refusal to vaccinate against more severe diseases has sparked debates that may overshadow challenges to the flu shot.
“The fact is the influenza vaccine is recognized as the least effective vaccine product on the market,” wrote Ted Kuntz in an open letter addressed to the Ottawa Citizen in 2017.
Kuntz is the vice president of Vaccine Choice Canada, a non-profit organization committed to exposing the dangers of immunization.
His statement came in response to a story by the Ottawa Citizen promoting the effectiveness of the flu shot.
Kuntz takes issue with this stance, arguing, wrongly, that the flu shot has proven utterly ineffective in past years and has no bearing on the rate of hospitalizations due to flu-related complications. Flu shots vary in effectiveness from year to year, but last year’s was better than most.
Kuntz wrote that, “The influenza vaccine has never conclusively shown to be effective in preventing the flu in anyone.” Later in the same letter, he suggested, contrary to scientific evidence, that the shot ultimately does more harm than good by increasing the risk of infection.
While the letter, which directly opposes the findings of Public Health Ontario and the Institute for Clinical Evaluative Sciences referenced in the article, clearly caters to a select corner of the population, its assertion that the flu shot is ineffective and unnecessary could resonate with more people than expected.
Vaccine complacency: a collective shrug in the face of infection
According to a Statistics Canada report on the 2015-16 flu season, 58 per cent of Canadians who did not receive the shot “said that they did not think it was necessary,” while an additional 14 per cent said that they “thought it would have no benefit.”
Ann Jolly, a professor of epidemiology at the University of Ottawa, does not interpret this as a sign of growing disillusionment toward the vaccine, but rather a reflection of Canadians’ perceptions of the virus itself.
“It’s more of a sign that most people don’t view influenza as a severe disease,” said Jolly. “A substantial proportion of people believe that the vaccine is unnecessary.”
In medical circles, this is referred to as “vaccine complacency,” wherein the perceived threat of infection is so low that the vaccine is considered unnecessary.
A young person in good health, confident in their immune system’s ability to fight off seasonal infection, may be less inclined to get the vaccine, as suggested by a 2018 Statistics Canada study. The results of this study found that individuals who saw their health as excellent, very good or good were less likely to get immunized.
“I’ve never actually gotten a flu shot,” said Jake Nixon, a 23-year-old student at the University of Ottawa. “I guess I just always figured that I was going to get sick anyway and that I could handle it. The flu really isn’t that bad.”
While this might be a viable approach for younger populations, it marks a departure from the objective of herd immunity, one that could have consequences for at-risk populations.
Who is at risk?
Senior citizens, who account for approximately 90 per cent of flu-related deaths each year in the United States, are more likely to receive the flu shot, as reflected by Ottawa Public Health data. Ottawa seniors have consistently posted higher vaccination rates than working age adults, averaging around 81 per cent coverage over the past five years.
That said, a combination of circumstances may make the upcoming flu season especially dangerous for the elderly, in spite of their best efforts.
Canada Public Health has already identified H3N2 as this year’s dominant flu strain, a virus deemed particularly dangerous for seniors. In anticipation of a severe flu season, the Ontario government ordered an increased supply of the high-dose vaccine, often administered to people over the age of 65. Due to a manufacturing issue, however, the delivery of approximately 300,000 doses has been delayed until early December.
According to Zara Masaud, a nursing student at the University of Ottawa, this delay might have a negative impact.
“Respiratory season normally starts in November,” said Masaud. “We normally try to get as many people immunized as possible before this point.”
In light of the delays, Masaud said that retirement homes and care facilities have been offered priority supply.
“But not all elderly people live in retirement homes,” she continued, saying that many seniors may still have limited access.
For Jolly, the fact that seniors will be left with limited access to the best defence against an aggressive flu strain only enhances the need for mass immunization.
“These delays will mean that some people will not get the vaccine when they should, but the biggest issue here is this decline in the amount of people getting immunized,” she said. “Raising the vaccine rates would have the biggest impact on public health.”
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Excellent article Warren! So proud of you!!!