Remember the lessons of the polio vaccine

CHRIS MacLEAN  –  Jan 12, 2021

As we await deliverance from the multi-faceted scourge that is COVID-19, we look to the vaccine as the holy grail that will return us to some semblance of normalcy. But we must not rush production beyond its capacity to produce and administer a safe vaccine.

Yes, thousands are dying every day, but our government leaders are spending every waking minute trying navigate myriad logistics complexities. 

The risk here is that governments may push producers so hard that mistakes are made.

We must heed the lessons learned in California in 1955 when the rush to get polio vaccines into arms backfired, creating new casualties instead of saving lives.

Polio is an incurable, contagious, viral illness that causes nerve injury. It can infect the spinal cord, leading to paralysis and sometimes death. In the late 1940s and early 1950s, North America was in the midst of a polio epidemic. Using a synthetic base developed in 1949 by scientists at the University of Toronto’s Connaught Medical Research Laboratories, Dr. Jonas Salk's work, at the University of Pittsburgh, on an inactivated polio vaccine that could stimulate the immune system enough to prevent polio in humans, took a giant leap forward. Human trials of the first experimental Salk vaccine began in 1952.

During this time, the Connaught research team was focused on large-scale cultivation of the poliovirus. In 1952, the National Foundation for Infantile Paralysis commissioned Connaught to expand its new poliovirus production methods.

In April 1955, the USA announced the successful results of its large-scale year-long field trials of the polio vaccine, and six producers rushed to release their vaccines to meet the demand. While each batch of the field trials had been carefully monitored and tested, not every batch of the new vaccine production was tested. Within weeks, 79 children who had received the vaccine from Cutter Laboratories in California contracted paralytic polio. On 8 May 1955, the U.S. Surgeon General suspended its vaccination program pending the outcome of an investigation.

In Canada, the question of continuing or suspending was hotly debated. The University of Toronto’s Connaught Medical Research Laboratories had developed the Canadian vaccine and was the sole producer of the vaccine in Canada. Paul Martin Senior, the Minister of National Health and Welfare at the time, argued that Connaught's long experience in developing the vaccine would ensure the stability of the product and thus, the safety to Canadians. Minister Martin and his son both suffered mild forms of polio as children, and his determination to eradicate the disease is well documented. The program was allowed to continue.

Although the exact cause of the Cutter disaster was never officially determined, the prevailing assessment is that "incomplete inactivation" of the poliovirus in selected lots at Cutter Laboratories was the cause of the problem. Production methods at this one laboratory did not follow instructions precisely and resulted in failure of some lots of its vaccine. No other lab had the same problem.

The vaccine had been thoroughly tested and was indeed safe, but the failure of one laboratory to produce it properly, led to thousands of American children becoming infected, 200 being paralyzed, and 11 dying. The U.S. program was eventually allowed to continue but new controls required manufacturers to test larger samples of each vaccine lot, to lengthen the time the vaccine was treated with formaldehyde, to use filters that would remove clumps of virus that might resist chemical inactivation, and to test the vaccine after bottling, among other changes.

The lesson here is not to rush production, and to ensure strict adherence to the production process and the vaccination protocols so the vaccine can be as safe as the heavily-monitored field trials were.

Our task is to be patient, follow safety measures (and hold accountable those who don't), and wait our turn.

Vaccines are life-savers when properly produced and administered. Let's take the vaccine as seriously as we view the virus.

Chris MacLean is the Editor-in-Chief at FrontLine Magazine