Seasonal influenza — the flu — sickens and kills many Americans in a good year, and this is already a bad one. According to the Centers for Disease Control and Prevention, since 2010, flu has annually caused “between 9.2 million and 35.6 million illnesses, between 140,000 and 710,000 hospitalizations and between 12,000 and 56,000 deaths.” In the 2017-18 season, which began in November and won’t end until March, hospital emergency rooms are overflowing, deaths are running ahead of recent years and pharmacies are low on the anti-flu drug Tamiflu and intravenous solutions needed to keep patients hydrated.
Vaccination ought to be the key to prevention. According to estimates from the CDC, in six influenza seasons starting in 2005-06, vaccination prevented 13.59 million cases. That looks impressive, but our current vaccines are barely adequate, and the nation’s drug regulators and science-funding agencies aren’t doing enough about it.
Because flu viruses mutate frequently, vaccines are reformulated each year to target the virus strains predicted to prevail during the coming fall and winter. How well the flu shot works depends on how accurate the prediction is. Since the 2004-05 season, the flu vaccines’ effectiveness has varied from 10 percent to 60 percent.
This year, the vaccine is an especially poor match, in part because what’s going around is predominantly a virulent strain called H3N2. Although that strain is targeted by this season’s flu shot, most of the vaccine is prepared from fertilized chicken eggs, a method known to reduce its effectiveness against certain strains, particularly H3N2.
We can do better.
Vaccines work by exposing us to non-infectious components of a virus — the viral antigens — that elicit an immune response. Regulators could encourage manufacturers to stop using chicken eggs and instead prepare vaccines in “cultured cells” — cells that are removed from animals and grown in controlled conditions. This method would produce vaccines with greater fidelity to the targeted flu strains.
We also need more research on “adjuvants,” chemicals mixed with the viral antigens to further boost our immune response.
But most of all, we need to accelerate research on the holy grail of flu prevention: a “universal” vaccine that would target a part or parts of the virus that remain unchanged among different strains, even during the virus’s rapid mutations. A universal vaccine has the potential to provide us with permanent protection from all strains of flu.
Several different approaches to a universal vaccine are being pursued, and the preliminary research is promising. Nevertheless, there is surprisingly meager federal research funding in this area.
A recent New York Times article, by Michael T. Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy, and writer Mark Olshaker, tracked the government’s investment in flu vaccine research: “The National Institutes of Health has publicly declared developing a (universal) vaccine a priority, (but) it has only about $32 million this year specifically for such research.” Another federal agency, the Biomedical Advanced Research and Development Authority, is spending $43 million on a single pro-ject in pursuit of “game-changing influenza vaccines.” These are minimal efforts when matched against the $1 billion spent annually on developing an HIV vaccine and the many billions that have been spent on vaccines for the Zika and Ebola viruses.
Within the vaccinated population, a vaccine’s effectiveness varies widely because it is affected by the general health and age of the recipient. Although people 65 and older make up only 15 percent of the U.S. population, on average, they account for about 60 percent of the hospitalizations and 90 percent of the deaths attributed to seasonal flu.
Seniors respond less well to vaccines than younger people because, as we age, our immune system functions less well. Scientists at the National Institutes of Health, after reviewing 31 vaccine response studies comparing groups of different ages, called for more potent formulations for the elderly. But exactly how strong the shot should be, and whether additional injections would boost immunity, requires more study. There is a flu vaccine for people over 65 that contains four times as much antigen as regular flu shots, and one that contains an adjuvant, but they have improved the shot’s effectiveness only slightly.
An increase in research funding on adjuvants, more effective dosing regimens and better production methods are simple changes that would better prepare us to face flu outbreaks. Increasing the funding for developing a universal vaccine is more challenging, but it promises much greater results. The fraught flu season of 2017-18 is a sign we need to conquer the disease once and for all.