One Vaccine Breakthrough in the 1960s Has Prevented 10 Million Deaths

The WI-38 development in 1962 changed the inoculation landscape by relying on human cells to develop the vaccine. Abid Katib/Getty Images
The WI-38 development in 1962 changed the inoculation landscape by relying on human cells to develop the vaccine. Abid Katib/Getty Images

It's not just young people who take their health for granted — these days, it's many of us in the developed world. Safe vaccinations now prevent outbreaks of what 50 years ago were common human diseases like polio and measles. Lately, though, the anti-vaccination movement in the United States has gained a mystifying amount of traction, considering the unbelievably scant amount of scientific evidence backing up its unproven claims that common vaccines cause autism.

And the anti-vaccination craze isn't harmless: A 2014 outbreak of measles in California, for instance, can be directly sourced to a single unvaccinated, infected 11-year-old's visit to a theme park, where she infected other unvaccinated children. Over the next year, 188 cases of measles in 24 states were reported in the U.S. — not all of them stemmed from this one California case, but many did. The point being, the rates for measles vaccination in the U.S. are now as low as 50 to 86 percent, with 96 to 99 percent being the target to reach "herd immunity." If enough people are foregoing vaccinations for diseases that were once largely dormant, like measles, they can pop back up and spread among the community through unvaccinated individuals.


In the face of this nonsense, a 2017 study published in the AIMS Public Health journal estimates exactly how many cases and resulting deaths from some once-common diseases were prevented by a single vaccine breakthrough. In 1962, researchers developed a human cell strain named WI-38 that allowed human vaccinations to be made for polio, measles, mumps, rubella, varicella, adenovirus, rabies and hepatitis A. According to the study's analysis, WI-38 prevented about 4.5 billion cases of disease and 10 million deaths worldwide between 1963 and 2015. In the U.S. alone, almost 200 million cases were prevented, sparing an estimated 450,000 lives.

The need for the human cell strain WI-38 stemmed from the fact that all vaccines before it were grown in monkey cells, a practice that carried with it the added risk of contamination by monkey viruses. Rather than chance that particular medical-disaster-film scenario, vaccine production was shut down until a human strain could be developed. The big discovery was made by Leonard Hayflick of the University of California, San Francisco, and swiftly applied through worldwide vaccination programs.

"Given the acknowledged large, positive global health impact of vaccines in general, I was curious what contribution my discovery of WI-38 in 1962 had in saving lives and reducing morbidity, since a large number of viral vaccines in use today are made with my cell strain or its derivatives," said Hayflick, one of the study's coauthors, in a press release.

Co-author S. Jay Olshansky, an epidemiologist and biostatistician at the University of Illinois at Chicago School of Public Health, was able to estimate the number of disease cases prevented and lives saved by Hayflick's breakthrough by looking back at prevalence rate data published for the diseases in 1960 (before the introduction of WI-38). Because the vaccines for the diseases came out at different times, Olshansky multiplied the number of years between each vaccine's debut and 2015 by the number of reported cases and deaths in 1960, and calculated the impact of each vaccine from there. And the answers to his calculations are objectively mind-blowing:

"There is no medication, lifestyle change, public health innovation, or medical procedure ever developed that has even come close to the life-saving, life-extending, and primary prevention benefits associated with vaccines," said Hayflick.

But one question remains: Why are some parents playing so fast and loose with their kids' and their community's health and well-being when we have these effective, life saving vaccines? Perhaps, Olshansky suggests, it's because we've forgotten past horrors and may be dooming ourselves to repeat them.

"It is possible that the anti-vaccination movement has arisen among younger generations, in part, because they cannot bear witness to the tragedy of disfigurement, morbidity, and death caused by viral and bacterial diseases," he said in the press release.