Source: Centers for Disease Control and Prevention (CDC)
As the COVID-19 epidemic continues to break records in the United States (where cases have surged past 10 million with deaths at ~250,000), the drug maker Pfizer has announced that an early analysis of its vaccine trial was more than 90 per cent effective in preventing the virus.
Scientists have been hoping for a coronavirus vaccine that is at least 75 per cent effective, and White House coronavirus advisor Dr. Anthony Fauci has said that 50 or 60 per cent would be acceptable. This means Pfizer’s impressive 90 per cent efficacy rate has exceeded the broader medical community’s expectations.
Palladium’s Dr. Farley Cleghorn is cautiously optimistic, telling Bloomberg TV on Monday, “This is not conclusive news. It’s encouraging but it’s not conclusive.”
According to a press release, Pfizer’s interim analysis evaluated 94 confirmed cases of COVID-19 in a total of 43,538 trial participants. With plans to continue their clinical trials until they reach a total of 164 confirmed cases, Pfizer will submit for the Emergency Use Authorization to the U.S. Food and Drug Administration once the required safety milestone of at least two months of follow-up for each volunteer is achieved towards the end of November.
These trials have moved rapidly thanks to the uptick in COVID-19 cases. “[Pfizer’s trials] are proceeding relatively quickly and the reason for that is because we have such a robust coronavirus epidemic in the U.S.,” Cleghorn said.
Cleghorn clarified that Pfizer’s vaccine uses a new and innovative technology called messenger RNA (mRNA) to produce an immune response in those who are vaccinated. “This allows antibodies and T-cell immune cells to be generated in response to the virus,” he explained. “But this vaccine does not prevent the transmission of the virus, it prevents the clinical outcome of the virus – COVID-19.”
Continuing Mitigation Behaviours
This means that even after distribution of a vaccine like Pfizer’s begins, our infection control measures (such as social distancing, hygiene, and mask-wearing) must continue.
“We will have to think very carefully about the impact that this vaccine will have on social distancing,” Cleghorn further told Times Radio. “We should all be encouraging people to continue avoiding transmission behaviours through Thanksgiving and Christmas. If this vaccine pans out, we’re well into next year or spring before we can reasonably distribute it to the people who need it most.”
Thinking Ahead to Distribution
Pfizer plans to take on both the manufacturing and distribution of the vaccine, which according to Cleghorn is a challenge on its own. But this vaccine presents a new challenge to the distribution process in that it must be stored and shipped at ultra-cold temperatures – minus 70 degrees Celsius to be exact.
“We’ve never had a situation like this where we need to transport a vaccine to people under super cold conditions. This is new,” he said.
This requirement poses an obstacle for even the most sophisticated hospitals and may severely limit where and to whom the vaccine can reasonably be administered.
Several allocation frameworks and guidelines exist for who should get the vaccine first, and Cleghorn recommends focusing on those who are most vulnerable and most likely to suffer the severe consequences of COVID-19.
“This vaccine does not stop the transmission itself; it reduces the morbidity and mortality associated with the virus. It’s very important for our frontline, healthcare and essential workers, as well as the elderly population to get access first.”
While many questions still remain on the vaccine’s long-term protection against COVID-19, the efficacy for those who have already contracted the virus, and how it will be distributed, Cleghorn remains hopeful that this is a step in the right direction.
Hear Dr. Farley Cleghorn discuss Pfizer’s interim results on Times Radio, beginning at 2:06:10. Contact firstname.lastname@example.org to learn more.