On Monday, Pfizer announced preliminary results from the phase 3 trial of the vaccine that it has developed with German company BioNTech, suggesting that it may be up to 90% effective at preventing Covid-19 with no serious safety concerns. The vaccine, which represents a new way to make a vaccine, might be ready for an Emergency Use Authorization from the FDA by the end of the year.
BioNTech’s vaccine is an mRNA (as in “messenger RNA,” which might ring a faint bell from high school biology class) vaccine, similar to one being developed by Boston-based Moderna as well as Translate Bio, which is partnered with pharmaceutical giant Sanofi. This type of vaccine has been in the works for other diseases, including the flu, but none have been approved for use by any regulatory body yet. Success with this platform has the potential to accelerate the development of vaccines for new diseases, a process which can typically take close to a decade.
Here’s what you need to know.
Pfizer’s vaccine is based on a new kind of technology
Traditional vaccines are made from dead or weakened versions of an infectious virus. This new type of vaccine is different. To develop it, the genes of the SARS-CoV-2 virus, which causes Covid-19, were first analyzed to locate the part that codes its “spike” protein, which is what enables the virus to infect people. The codes for that protein are then isolated and copied as mRNA fragments, which is what cells use as instructions for making proteins. Those fragments are packaged up into special molecules, then injected into the patient’s cells.
Within the cells, the mRNA comes into the body’s protein factories, called ribosomes. The ribosomes “read” the mRNA, and follow its instructions to make copies of the spike protein. Those copies of the spike protein can’t, by themselves, cause harm. But they’ll trigger the body to make antibodies against the virus. Those antibodies, in turn, will protect patients from a Covid-19 infection. At least, that’s the idea.
The vaccine still needs to be approved by the Food and Drug Administration
Before the vaccine can be distributed, it has to first be approved by appropriate regulatory bodies. In the United States, that’s the FDA. Pfizer has said that it intends to seek an Emergency Use Authorization from the FDA to enable distribution and administration of the vaccine in late November, at which point the company will have an average of two months’ worth of safety data for each patient. That’s because most bad reactions to vaccines happen shortly after infection. Additionally, Pfizer will continue to monitor the patients in its study for two years after the vaccine administration.
Distributing this vaccine is more complicated than for a typical vaccine
Although one advantage of mRNA vaccines is that they’re potentially faster to develop than traditional vaccines, their administration and distribution is scads more complicated. For example, the Pfizer vaccine is currently being tested on a two-dose schedule, 21 days apart, unlike the single dose of a typical vaccine for diseases like the flu. The 21-day separation has raised some concerns about the patient compliance needed for vaccines to work.
For long-term storage, the vaccine has to be kept at very cold temperatures—around –70° Celsius (–94° Fahrenheit), which requires a specialized freezer. (Flu vaccines, by contrast, can usually be stored in a refrigerator.) The company has developed a specialty thermal shipping container, which can be kept cold with dry ice and be used to store the vaccine doses for up to 15 days. If long-term storage isn’t required, Pfizer’s vaccine can be stored in a refrigerator, but only for up to five days.
Pfizer footed the bill for its own part of vaccine development
Several companies, such as Moderna, have received federal funding and support for the development of their vaccines and treatments through the research and development process. Pfizer opted out of that, choosing instead to spend $1 billion of its own money to move the vaccine forward. “A billion dollars is not going to break us,” CEO Albert Bourla told Forbes earlier this year.
That said, BioNTech did receive a $442 million grant from the German government to help develop the vaccine. And in July, the two companies signed an agreement to sell at least 100 million doses to the U.S. Department of Health and Human Services (HHS) for $1.95 billion. The country of Spain has initially secured 20 million doses of the vaccine as well.