Morgan Stanley biotech analyst Matthew Harrison weighed in on the COVID-19 vaccine situation as timelines are drawn-out. Harrison believes COVID infections are lower in vaccine trial participants compared to the local populations at the clinical sites, which delays the initial interim analyses. That said, the firm still sees clear trial data in November.

"We now assume trial infection rates are 50% lower than the general population, which delays the initial interim
analyses by ~3 weeks," Harrison said.

Harrison highlights that Pfizer (NYSE: PFE)/BioNTech SE (NASDAQ: BNTX) has not yet accrued the 32 COVID infections for its 1st interim analysis.

"The fact that Pfizer's first interim has not been triggered suggests the participants enrolled in the trial may have lower exposure to COVID-19 compared to the general population and/or reported COVID infections overestimating the rate of
symptomatic infections," the analyst commented. "We adjusted our assumptions on the infection rate in the trials by reducing the locally observed rates by 50%. We chose 50% because recent studies have suggested universal mask wearing would cut transmission by ~49% and it appears trial participants are taking more risk mitigation steps compared to the local population."

The analyst expects that both Pfizer and Moderna (NASDAQ: MRNA) could provide 50-60 million doses of the vaccine by the end of 2020.

"Pfizer CEO Bourla indicated that Pfizer has produced hundreds of thousands of doses so far and expects to have 30-40M doses by YE20," the analyst commented. "Moderna had previously commented that it expects to have ~20M doses by YE20. Thus we expect the initial EUA could cover 25-30M people in the US."