Standard practice for most jurisdictions that promote and administer influenza vaccination programs is to concentrate particularly on immunizing statistically high-risk individuals — the elderly, the very young, and people with chronic illnesses and/or compromised immune systems.
However, an an Assistant Professor in the Department of Economics at Dalhousie University in Halifax, Nova Scotia, Canada, says there is strong evidence supporting expansion of flu vaccine coverage to other demographics, especially young, healthy persons — a cohort who suffer the lowest personal cost associated with becoming infected with the flu. Dr. Courtney Ward says that getting vaccinated not only helps protect such persons from getting the flu themselves, but also confers the secondary benefit of them not passing the infection on to others who may be in less robust health. Dr. Ward says her research has conformed that the greatest magnitude of social and economic cost benefit, particularly secondary benefit is realized through vaccinating younger, healthier people, not only helping protect them directly, but also having a substantial flow-through effect in fewer doctors office and ER visits and hospital admissions.
A possible explanation for that would be that the young and healthy are more active and mobile, and thus more likely to pass flu on to a greater number of others. In an excerpt form another, work-in-progress paper posted on her Website, titled “Influenza, Vaccination and Externalities for Long Term Care Residents.” Dr. Ward comments that public policy makers often rely on group-specific evidence from randomized control trials in designing vaccination campaigns. and in gauging their expected impact. However, she notes that even where trials are informative of vaccine effectiveness by group, optimal policy design may run counter to this evidence depending on the nature of vaccine externalities. For instance, she cites previous literature on the influenza vaccine and mortality that finds high effectiveness for residents of long term care homes, suggesting this group for targeted policy. However, depending on the nature of externalities across group, this approach may yield low relative gains. Her paper addresses this question by using hospital records over the last decade and focusing on the introduction of a broad based vaccination program in the Canadian province of Ontario, she finds evidence that vaccination of younger groups leads to large mortality gains for residents in long-term care homes, indicating that substantial external gains for this group are still possible even where vaccination rates are in the excess of 90 percent.
So why is an economist academic focused on influenza? Dr, Ward explained in a televised interview with CTV Atlantic’s Kayla Hounsell that economics is about human behavior, and deciding whether or not to get a flu vaccination, or deciding at the policy level who will and who won’t get vaccinated involves behavior. She notes on her Dalhousie U. Web page that as an an applied economist working the in the area of labour and health, the focus of her work is on the implications of externality and selection effects in health production, and s particularly interested in how aspects of externalities and selection can interact with policy in intended or unintended ways. She continues noting that health policy is often based on evidence estimating the effectiveness of health interventions, and that in some cases, this evidence is parsed by demographic factors that suggest different approaches to policy design by group status (e.g. age, location). Her research focuses on the implications of externality and selection effects in health production, and her work has particular emphasis on how these aspects interact with policy in intended or unintended ways.
Some of Dr. Ward’s research findings were published in the January 2014 edition of the American Economic Journal: Applied Economics, in a paper entitled “Influenza Vaccination Campaigns: Is an Ounce of Prevention Worth a Pound of Cure?” (Applied Economics, 6(1): 38-72. DOI: 10.1257/app.6.1.38).
In the paper’s abstract, Dr. Ward notes that using a triple-difference design, which exploits the introduction of a broad based vaccination program in Ontario and the quality of the vaccine from year to year, she links higher vaccination rates to general public health improvements, and that her research results indicate: (i) coverage expansion leads to large excess gains for program regions; (ii) benefits exhibit decreasing returns corresponding to a standard model of disease dynamics; and (iii) substantial external benefits accrue to older adults.
Dr. Ward expands on the topic in an article published by the London School of Economics and Political Science USAPP – American Politics and Policy blog, she notes that In recent flu seasons, the vaccination rate in older Americans has exceeded that of healthy working age Americans two and a half times over, but the medical care burden for older adults nevertheless still outpaced that of younger demographics , and millions of susceptible younger adults came down with the virus.
Acknowledging that the concept of vaccines offering benefits extending beyond the direct effect is not new, Dr. Ward observes that without evidence on how benefits of flu vaccination manifest across different groups, policy makers have been flying blind and guessing how to proceed. For example, she says that when Ontario expanded vaccine recommendation and coverage across the province’s entire population in 2000, many commentators parsed the move as defying the rules of evidence-based decision-making, and that with critics of the new policy pointed to an accumulation of research indicating higher benefits of vaccination in more vulnerable groups.
On the other hand, while it can’t be gainsaid that flu infections in more vulnerable demographics will tend towards more costly medical care, Dr, Ward suggests that healthy people with stronger immune responses may derive a higher degree of protection from the same shot and then leverage that protection over a larger network of people. Therefore while influenza infections will cost more per individual in vulnerable groups, and that by focusing flu vaccination incentives solely on the most vulnerable groups, it’s arguable that everybody loses out overall.
Dr. Ward says it’s fortunate that Ontario flu program went against conventional wisdom and even existing evidence on vaccination targeting, because it gave back by providing years of evidence on flu epidemics under a policy of universal coverage – a history that can help us understand the impact of a universal approach to vaccination policy.
You can read the entire blog entry at:
CTV Atlantic News
London School of Economics and Political Science USAPP – American Politics and Policy