As vaccines for COVID-19 began making their way to front-line workers and other vulnerable populations on Monday, there is for the first time in a long time, reason to be hopeful that this pandemic will come to end.
Two vaccines, one each developed by pharmaceutical giants Pfizer and Moderna, have shown tremendous promise through their clinical trials on their way to FDA approval.
“I think this is a well-tolerated vaccine,” said Dr. Francis Riedo, Medical Director of Infection Control and Prevention at EvergreenHealth. “Neither study was interrupted because of a serious adverse event. In the end, it was found to be 95% protective in preventing symptomatic infection.
“The beauty of having two studies of course is you essentially repeated the scientific experiment twice – two different companies, they're competitors using similar technology, a slightly different variation, have come up with essentially the same answer. It's remarkable in terms of not only how effective it is, but also how safe it is and so I think this is very promising.”
The vaccines require two doses for total immunization. The Pfizer vaccine is administered 21 days apart, the Moderna 28 days apart. Many folks are wondering if both doses are necessary.
“The two-dose regimen is required because it turns out the first dose primes the immune response, and it's that response that is then boosted by the second dose,” Dr. Riedo said. This is quite common among vaccinations -- to name a few, hepatitis A, hepatitis B, a tetanus, diphtheria, pertussis, polio all require two or more doses.
There are several more potential vaccines currently undergoing their clinical trials -- but just these two reveal a significant step towards herd immunity, which is achieved when 70 to 80 percent of the population is protected from either direct infection or through immunizations.
“I think all we have to do is look around and see how devastating this pandemic has been in terms of the direct infection route, it's not the way we want to develop herd immunity," explained Dr. Riedo. “A vaccine that is safe, effective and will protect the population against infection is far preferable to waiting for everyone in the country to become infected naturally. Really, it's time to go on offense here and start protecting our population rather than just playing defense all the time.”