Why it's crucial we don't forget about flu in the COVID-19 pandemic

Efforts to find a vaccine for COVID-19 will enter a decisive lap in the summer, when phase 3 trials on humans for four vaccine candidates will begin, The Wall Street Journal reported last week. These human trials will feature vaccines developed by Moderna, Johnson & Johnson, and joint projects of AstraZeneca-Oxford University and Pfizer-BioNTech.

Amid all the anxiety over finding treatments for COVID-19, is the influenza virus getting the short end of the stick from policymakers in terms of investments in mitigation? In fact, flu mitigation needs more attention from policymakers, according to recent research by Wharton finance professor Jules H. van Binsbergen and Christian C. Opp, associate professor of finance at University of Rochester’s Simon Business School.

In their paper, titled “The Effectiveness of Life-Preserving Investments in Times of COVID-19,” Binsbergen and Opp weighed the effectiveness of preventive investments aimed at increasing life expectancy in mitigating influenza and COVID-19. They have made a case for “widespread influenza vaccination” based on their estimates of the “marginal effectiveness” of investments in mitigating both flu and COVID-19.

Their research model computes the amount of investment resources that would be needed to save an equivalent number of life years in mitigating both viruses. “Maximizing overall life expectancy requires allocating resources across hazards so as to equalize investments’ marginal effectiveness,” they noted.

At last count on June 14, the COVID-19 pandemic had resulted in nearly 2.1 million cases and claimed more than 115,000 lives in the U.S. According to estimates by the U.S. Centers for Disease Control and Protection (CDC), the 2019-2020 flu season (which ended in April) claimed between 27,000 and 62,000 lives.

“If you’re interested in saving lives, then flu vaccinations seem to be a particularly effective way of saving a lot of lives going forward,” said Binsbergen. He noted the growing concerns over how the health care infrastructure would cope if a second wave of COVID-19 arrives in September. “A lot of people are already in hospitals during a typical flu season,” he said. “It seems even more important to avoid that interaction, and invest more heavily in flu vaccinations to free capacity to tend to new COVID patients.”

How Mitigation Helps

Life hazards can be reduced in various ways, including vaccination, research, health care coverage, and behavioral changes. “Yet, scarcity of resources implies that society always faces tradeoffs,” the paper noted. “Even when maximizing life expectancy is the only policy objective, doing everything possible to mitigate any one particular hazard, while ignoring others, is generally suboptimal.”

Mitigation helps in two ways by slowing the pandemic, or “flattening of the curve,” the paper stated. First, it provides time for the health care sector to develop treatments and vaccines. “A lower fraction could end up getting infected if a vaccine became available during the time won by slowing the evolution of the pandemic,” the researchers said. Second, mitigation lowers peak demand for medical treatments from hospitals, thereby ensuring that fatality rates do not increase due to capacity shortages. Focusing investments on any one “hazard” would generally cause more deaths than if they were spread across different areas, they added.

The research weighs outcomes of mitigation investments in terms of population distribution by age groups, life expectancy, the number of deaths by cause and age, and the number of life years lost because of deaths. Of the roughly 2.8 million deaths in the U.S. in 2017, the major causes of were heart disease (647,457), cancer (599,108) and accidents, including those related to traffic (169,936), while 55,672 people died of flu and pneumonia. Flu deaths are estimated at 61,000 for the 2017-2018 flu season, the paper noted. The study sourced its data from the Census, the National Vital Statistics Report and the U.S. Centers for Disease Control and Prevention.

Binsbergen and Opp studied the rates and effectiveness of flu vaccination for the past 10 flu seasons. With mandatory vaccination, an estimated 156,000 life years could have been saved in 2017 alone, and up to 643,000 life years had it achieved full herd immunity across the entire U.S. population, they concluded. Such mandatory vaccination would cost $3.85 billion to cover some 192 million people in the U.S. who are currently not vaccinated, assuming a price of $20 per dose, according to the study.

Drawing from that, it put the “cost per life year” gained from influenza mitigation for the average flu year at $36,607. By comparison, the cost per life year gained from COVID-19 mitigation works out to $41,730.

Binsbergen clarified that his paper is not suggesting whether COVID-19 should get more or less investments in mitigation. “The combined economic cost that we are spending on fighting COVID is already in the trillions of dollars,” he said. (The three rounds of coronavirus relief packages announced by the Trump administration and Congress exceed $2 trillion.) “What I want to say is if we’re willing to invest this much in COVID, we should certainly be willing to invest $3.85 billion on flu vaccination.”

Eventually, it is a question of tradeoffs. “With risk management, you cannot reduce all risks to zero,” said Binsbergen. “That’s not possible because there are just not enough resources to do that. So you always have to make calculated choices and try to address particularly those that you think pose the greatest risk.”

Binsbergen noted that while COVID-19 is currently getting a lot of media attention, “the side effect” is that other concerns may not get the attention they need. “With all the flu deaths that we have every year and all the life years lost year after year, we’ve become accustomed to it,” he said. “So we don’t think about those life years lost anymore. But that doesn’t mean that they’re not lost too.”

“For a relatively small amount of money – $3.85 billion – you could save thousands of life years that are otherwise lost through the flu. This is not a large amount compared to the current investments in COVID, which are in the trillions of dollars,” he said. The investment in flu mitigation “seems low relative to its effectiveness.”

Why Outcomes May Vary

In practice, the “marginal effectiveness” of investments may vary across different types of hazards, or diseases. The paper identified a few possible explanations for those variations. In the case of COVID-19 mitigation efforts, policymakers will find it difficult to fine-tune rules to make them simple enough for large groups of people to follow. In contrast, in the case of influenza, the costs of vaccines are predictable, the paper noted. Yet another factor that could impact how mitigation investments pay off are “behavioral biases,” where people may neglect smaller risks but give more importance to other hazards. For example, “seeing pictures on television and on social media may lead to a subjective over-representation of risks associated with COVID-19,” according to the paper. But the lack of coverage of other relevant hazards may lead to an underestimation of those risks, the researchers add.

Finally, “institutional frictions” could also skew investments in mitigation. For example, politicians who want to stay in office may direct investments to a particular disease, or hazard, leading to uneven outcomes, the paper stated.

However, even after accounting for the above possible distortions, the authors’ analysis “suggests that widespread influenza vaccination would be a highly effective life-preserving investment.”

Why the Flu Needs Urgent Attention

The push for flu mitigation is all the more important because vaccination rates among adults have been declining consistently in recent years. Surprisingly, fewer than half of all adults got themselves vaccinated against the flu in the 2017-2018 season, the study noted. In fact, the vaccination rate was a little shy of 27% for adults in the 18-49 age group.

Binsbergen spelled out what that low vaccination rate means in the context of COVID-19. “Suppose we get similar enthusiasm for COVID vaccination as we’re currently seeing for flu, that would not be good because that would mean that only 39% of the people would get vaccinated against COVID.”

“We hope that regulators will take flu vaccinations more seriously,” said Binsbergen. He therefore suggested increased levels of flu vaccinations. “The government could pay for those at a very small investment and make them free for everybody. Campaigns to get people flu vaccinated would also really help,” he said.

Influenza and COVID-19 present themselves in similar ways, the paper noted, citing the World Health Organization: a respiratory disease that could range in illness from asymptomatic or mild to severe disease and death. Both viruses are transmitted by contact, droplets and fomites. Preventing infection also calls for the same public health measures: hand hygiene, good respiratory etiquette, such as coughing into your elbow or into a tissue and immediately disposing of it and avoiding interaction with vulnerable groups such as the elderly when sick.

It of course helps to have timely investments in mitigation such as developing a vaccine.

One person who has regrets on that score is Peter Hotez, co-director of the Center for Vaccine Development at Texas Children’s Hospital and dean of the National School of Tropical Medicine at the Baylor College of Medicine in Houston. In 2016, he and his colleagues wanted to develop a vaccine for “a deadly strain of coronavirus,” but they couldn’t find willing investors for the $3 million they need to test their vaccine candidate on humans, according to an NBC News report.

“Right now, we’re all feeling that more should have been done – but that is after the fact,” said Binsbergen. “But in all fairness, there have been influential people who have been indicating that this would become a problem. They’ve tried hard to indeed increase funding for it, and they now regret that they didn’t push even harder. Bill Gates is one of them, of course. At least we should listen to those people about why they felt that way and learn our lessons from that going forward.”