Moderna CEO Stefan Bansel said in a statement that the results provided “the first clinical confirmation that our vaccine can prevent Covid-19 disease, including severe disease.”
Both Pfizer and Moderna announced the results in newsletters, not in scientific journals, and the companies have yet to release the detailed data that would allow outside experts to assess their claims. Therefore, the results cannot be considered conclusive. Studies are ongoing, and efficacy figures may change.
The company’s products open the door to a whole new way of producing vaccines – and making them fast. They both use a synthetic version of the coronavirus’ genetic material, called messenger RNA or mRNA, to program a person’s cells to make multiple copies of a portion of the virus. This shrapnel alarms the immune system and stimulates it to attack it, if the real virus attempts to invade. Although a number of vaccines that use this technology are in development for infections and other types of cancer, none have been approved or marketed.
“The fact that two different vaccines were manufactured by two different companies with two different types of structures, in a new concept of messenger RNA, both work effectively confirms the concept once and for all that this is a viable strategy not only for Covid but for the future,” said Dr. Barry R. Bloom, Harvard Professor of Public Health: “The Threats of Infectious Diseases.”
One of the important findings is that the vaccine appears to prevent severe disease, said Natalie E Dean, a biostatistician at the University of Florida. Pfizer did not release information about disease severity when reporting its findings.
Researchers say positive results from Pfizer and Moderna hold promise for other vaccines, because all of the candidates being tested are aiming for the same target – the so-called spike protein on the coronavirus that it uses to invade human cells.
Dr Bloom said that the success of the two vaccines meant that the immunoassays used in earlier stages of studies – participants’ antibody levels – were reliable, and that other companies could use these measures as evidence of effectiveness to shorten the testing and approval process for their vaccines.