The golden age of vaccine development

This article appears in issue 22 of Works in Progress magazine, which will be released this month. Subscribe here to receive it in print.

In 1796, when Edward Jenner developed the first vaccine, against the smallpox virus, no one knew what viruses were, let alone connected them to diseases.

Many believed Jenner’s vaccine worked because it depleted the body of the specific nutrients the disease needed to thrive. In reality, his concept worked because of the good fortune that cowpox infections provided cross protection against smallpox. It would take almost a century to work out how to develop vaccines against other diseases.

Stocks of Jenner’s vaccine would die out repeatedly, and needed to be rederived from scratch many times. Keeping a vaccine alive in the nineteenth century was grueling, requiring arm to arm chains of transmission just to preserve the material.

The process improved slowly. In the 1840s, doctors invented a method to grow the smallpox vaccine virus more safely and reliably on the skin of calves. The 1890s saw a method to keep it from spoiling quickly by mixing it with glycerin, and in the 1940s, scientists learned how to freeze-dry it to survive heat and long journeys. In the 1960s, the bifurcated needle, with a forked tip that could hold a tiny drop of vaccine, made it possible to use only a quarter of the usual dose and helped scale up vaccination. Technological innovations like these made it possible to eradicate smallpox worldwide.

Jenner’s discovery in the eighteenth century transformed the world. But it also reflected the primitive knowledge and technology of the time. It would take another 90 years for scientists to formulate germ theory. Another half century would pass before Ernst Ruska and Max Knoll invented the electron microscope, allowing scientists to see the virus that caused smallpox for the first time.

Two hundred years ago, vaccines were serendipitous; today, they are designed. We can now visualize the structure of pathogens at an atomic level. We can purify and design ingredients, boost our immune response with adjuvants, deliver vaccines in safer packages, and manufacture them in billions of doses. We can track pathogens’ evolution in real time and adapt vaccines to new strains.

It has never been easier to develop new vaccines. We are living through a golden age of vaccine development. The future holds even greater breakthroughs, but only if we continue ...