Over the past two weeks, two experimental vaccines have demonstrated efficacy of 95% in preventing cases of COVID-19.
Pfizer and BioNTech reported that their vaccine candidate demonstrated 95% efficacy in a Phase III trial, which meant that there were 95% fewer cases of symptomatic COVID-19 among trial participants who received the vaccine than among those who received the placebo. The results were measured seven days after the second vaccine dose; eight cases of COVID-19 were found in participants who had received the vaccine versus 162 in those who received the placebo. The efficacy was 94% in adults over age 65. Pfizer’s vaccine requires two doses administered 21 days apart. The company also reported that the efficacy was consistent across age, race and ethnicity demographics.
Moderna announced that its vaccine candidate demonstrated a 94.5% efficacy rate in preventing COVID-19 when assessed 14 days after the second dose (Moderna’s vaccine is administered in two doses 28 days apart). The Moderna analyses were interim, meaning that the company assessed the data when a predetermined number of COVID-19 infections had occurred across all participants in the trial. The final analysis for the primary endpoint in the Moderna trial will occur when 151 infections have been recorded.
Because minorities are more at risk for severe outcomes from COVID-19 (Black individuals account for 31% of COVID-19-positive hospitalizations; Hispanic or Latinx individuals make up 23%, according to the Centers for Disease Control and Prevention), both companies have tried to recruit a sizable proportion of minority participants. Pfizer said it achieved an overall proportion of 30% minority representation in the US, including 10.1% Black and 13.1% Hispanic and Latinx. Moderna said 20% of its trial participants were Hispanic and Latinx; 10% were Black.
The companies plan to follow participants for two years to assess the long-term safety and efficacy of their respective vaccines (see the Pfizer/BioNTech and Moderna trial protocols). Both vaccines rely on messenger RNA (mRNA) to encode harmless segments of the spike protein found on the SARS-CoV-2 coronavirus, which causes COVID-19. Upon injection, the mRNA is delivered to cells which then use the mRNA as a blueprint to make these protein segments, activating the body’s immune response against the virus. The technology is new; there are no approved mRNA vaccines or therapies for use in humans in the US or elsewhere.
The FDA has said that a COVID-19 vaccine awarded emergency use must demonstrate at least 50% efficacy and that an emergency use authorization (EUA) application must include interim analysis of at least 50% of participants with two months of follow-up for safety and effectiveness. A meeting of outside experts convened by the agency last month said it would like to see at least two more months of safety and efficacy data as well as a subgroup analysis of minorities.
EUA applications for both vaccines are expected to be submitted soon. The FDA has said it would hold an advisory committee meeting to get feedback from a group of external experts on any COVID-19 vaccine EUA, and Pfizer said that such a meeting is likely to be in December.
With the efficacy threshold cleared, distribution plans for the vaccines are coming into focus as manufacturers, states and others prepare to manage vaccines with different storage and handling requirements.
Pfizer and BioNTech’s vaccine must be kept at -70 degrees C; Moderna’s must be stored at -20 degrees C, which is similar to some pediatric vaccines. Some rural communities and states have raised concern about the ultra-cold storage needs, but Pfizer has developed specialized freezer packaging to keep the vaccines at the appropriate temperature for 15 days and is doing a dry run with the packages in four different states with both urban and rural geographies.
HRI’s analysis of the vaccine supply chain found that gene and cell therapies with ultra-low temperature requirements, similar to that of the Pfizer vaccine, are administered in facilities in many US metropolitan areas and could serve as hubs for distribution of Pfizer’s vaccine.
The federal government has asked states to figure out the nitty-gritty details of designating vaccination sites and exactly who should be first in line. Additionally, HHS announced a partnership with 19 chain and independent pharmacies to receive vaccine allocations and serve as vaccination sites, which the department said covers about 60% of pharmacies in the US.
With the pandemic accelerating the shift in consumer site-of-care preferences, COVID-19 vaccination models may need to take a consumer-centric approach with options such as mobile, retail or worksite clinics. In HRI’s September consumer survey, among those who said they would get a COVID-19 vaccine within the first year it was available, 49% selected a retail clinic among their top three preferred settings; 35% selected their pharmacy; and 17% selected worksite clinics.