To Guarantee Safety Of Covid-19 Vaccines, Prioritize Long-Term Studies
by William A. Haseltine
In the past few weeks, Covid-19 vaccines created by Pfizer and Moderna have made headlines with their promising phase 3 trial results. Neck-in-neck in efficacy, both reported reductions in Covid-19 related disease higher than 90 percent. The Food and Drug Administration (FDA) could open the doors to widespread use of these vaccines, either through expanded access or emergency use authorization, as early as next month.
Although the reviews leading up to a stamp of regulatory approval are proceeding full speed ahead, one last bend in the road awaits—phase 4 (see Figure 1). This stage is designed to catch any adverse effects that didn’t surface or register as significant over the course of clinical trials. It also involves monitoring the production of the vaccines themselves. Given the accelerated timeline, long-term followup will be of particular importance for any Covid-19 vaccine authorized for human use under any authority, and a new commentary in Science Magazine shows why.
Figure 1: A timeline of safety evaluation for vaccines, adjusted to reflect the current pace of ... [+] AUTHOR
While vaccines may be one of the most successful scientific technologies ever invented, the authors acknowledge, throughout history several have failed us. Many of the vaccine regulations we have today were borne of lessons learned the hard way—a contaminated batch that went on to infect thousands, or a rare side effect far more prevalent than initially perceived. A vaccine that fails to serve its original purpose, the safe prevention of disease, doesn’t just damage human health. It also triggers a loss of public confidence and fuels the rejection of future vaccines. But these fatal mistakes, contrary to what proponents of the anti-vax movement believe, are entirely avoidable, so long as we take care not to repeat them.
Sometimes the issue isn’t necessarily the vaccine technology itself, but a fundamental lack of quality control. Take, for instance, the so-called Cutter Incident of 1955. Cutter Laboratories was one of the pharmaceutical companies licensed to manufacture the Salk polio vaccine, which successfully used inactivated virus to stimulate bodily defenses against a horrific disease. Two of their batches, however, were mistakenly loaded up with live virus—poised, in other words, to spread polio rather than stop it. Those two batches alone went on to infect about 40,000 people, paralyzing 51 and killing five.