The coronavirus vaccine developed by Pfizer Inc. and BioNTech seems to be more than 90% effective in protecting people from Covid-19. This is a much higher percentage than many experts anticipated. The results are not fully completed, but it is a first step for a vaccine that will likely be cleared for a broader use. If the pending analysis indicates that the vaccine is safe, Pfizer says it will ask health regulators for permission to sell the shot before the end of this month. Regulators have indicated it will take before it can go into distribution. Once approved, it may also take months for companies to make enough doses of the vaccine for the general population.
The key information:
The vaccine from Pfizer and BioNTech uses a new gene-based technology known as mRNA. In a traditional vaccine, the patient is injected with weakened or inactivated versions of the virus. The immune system responds by producing specialized antibodies that are adapted to recognize the virus. After vaccination, the antibodies remain in the body. Then if the patient becomes infected with the actual virus later on, the antibodies can identify and help neutralize it. The Pfizer vaccine is a little different due to the unique nature of COVID-19. Instead of using the whole virus to generate an immune response, mRNA vaccines rely on coronavirus’s outer spike proteins, which are what antibodies use to recognize the virus. Scientists have been able to separate the genes in coronavirus responsible for producing these spike proteins. The genes are encased in lipid coating, which helps protect them from degrading. The genes are injected into a patient where they enter healthy cells and produce coronavirus spike proteins.
Once exported from the cells, the spike proteins prompt the immune system to mount a defence, just as with traditional vaccines.
The study:
The study to develop this vaccine has enrolled nearly 44,000 subjects. The findings involve a look at 94 people in the trial who contracted coronavirus and had at least one symptom of coronavirus. For the final analysis, 164 study subjects need to become infected and develop at least one symptom. Pfizer didn’t disclose exactly how many of the 94 subjects in the analysis received the vaccine or a placebo, but in the entire study, half receive the vaccine, while the other half receive a placebo. The two-dose vaccine was found to be more than 90% effective at seven days after the second dose, Pfizer reported, meaning that subjects were protected four weeks after their first shot. Pfizer has said some subjects in its earlier study of the vaccine reported side effects such as fatigue, headaches, and chills, but that there were no other serious side effects.
It is also important to note that the length of the protection the vaccine appears to provide is undetermined since researchers haven’t been studying volunteers for very long. However, Pfizer plans to monitor patients for two years after their second dose for safety and vaccine duration.
The review of the vaccine’s effectiveness and safety was performed by an outside panel of independent experts known as a data safety monitoring committee. The committee’s findings were then shared with Pfizer and BioNTech.
The Next Steps:
The findings and development of this type of vaccine came too quickly for researchers to properly assess the safety of the potential drug.
According to the U.S. Food and Drug Administration, there must be two months of vaccine monitoring of at least half of the study’s subjects for side effects before the vaccine can be distributed. Pfizer said it is still on track to collect at least two months of safety data during the third week of November and could file for an emergency authorization shortly after. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia, who is on an FDA vaccine-advisory committee, stated, “You have to be encouraged by this. It certainly looks like things are trending in the direction for protection.” He urges that the next steps should center around learning how well the vaccine works in high-risk groups, such as the elderly and diverse populations. Researchers have maintained that for vaccines to be effective they must work across age groups, races, and ethnicities.
Other vaccines:
While Pfizer’s vaccine seems to be the most promising, other vaccines are being developed from Moderna, Johnson & Johnson, and British drugmaker AstraZeneca. Moderna’s vaccine also uses the mRNA technology that Pfizer’s does. “This is great news as it shows mRNA can work,” Moderna Chief Executive Stéphane Bancel stated. “Great day for the world, as we are all waiting for vaccines.” The mood in the medical world remains resoundingly positive. Professor John Bell, a health-policy adviser to the U.K. government from the University of Oxford who led Oxford in reaching its Covid-19 vaccine deal with AstraZeneca, said, “The most important message is that you can make a vaccine against this critter.”
Sven Franssen