The German biotechnology company BioNTech and the US pharmaceutical company Pfizer announced on Monday the first promising results of their phase 3 clinical trial for a vaccine against SARS-CoV-2, the virus that causes covid-19.
These first results are what is known as “intermediate analysis”. It’s an early look at the data before a study is completed, to understand if there is any indication whether the vaccine might work.
Currently, this trial has enrolled 43,538 volunteers, giving half of the volunteers two doses of the vaccine and the other half two doses of a placebo. These volunteers then went on with their normal lives, but were monitored for any symptoms of Covid-19, with tests that have to be confirmed.
Analysis of 94 volunteers with confirmed COVID-19 suggests that the vaccine is more than 90% effective.
This means that if ten people who were to become ill from COVID-19 were supplied, only one in ten would become ill.
Do we have reason to hope?
Data is still missing. The news comes from a press release and the data has not undergone a “peer review” through a scientific publication, although it has been evaluated by an independent monitoring board.
The study will also not be complete until 164 volunteers have confirmed they have COVID-19, and therefore the estimate of efficacy may change.
Finally, volunteers must be monitored for a defined period of time after vaccination for any side effects and this must be completed.
Important questions also remain. It is not clear how long the protection will last as this study has only been going on for three months. It is not clear if this vaccine protects against severe symptoms or if it will work the same against all. For example, a phase 1 clinical trial with this vaccine showed that immune responses were lower in older people.
But the 90% efficiency is surprising. To give a bit of context, the FDA (the US drug agency) indicated that it would authorize a vaccine against SARS-CoV-2 with an efficacy of 50%. The flu vaccine often provides about 60% effectiveness and the mumps vaccine, which is currently the fastest ever made (in four years), provides about 88% effectiveness.
The BioNTech / Pfizer vaccine could surpass that, after just nine months of development. This level of effectiveness means that the transmission of the virus could be controlled very effectively.
That excites the research community. It bodes well for other vaccines currently being tested for SARS-CoV-2 and we could end up with several successful vaccines. This would be great because some might work better in certain populations, like older people.
Various vaccines could also be manufactured using existing infrastructures, speeding up vaccine distribution.
Produce mRNA on a commercial scale
The BioNTech / Pfizer vaccine is what is called an mRNA vaccine.
As this article by Professor Archa Fox, an expert in molecular cell biology at the University of Western Australia explains:
“MRNA vaccines are mRNA-coated molecules, similar to DNA, that carry the instructions for making a viral protein.
After injection into the muscle, the cells absorb the mRNA. Ribosomes, the cell’s protein factories, read the instructions from the mRNA and produce the viral protein. These new proteins are exported from cells and the rest of the immunization process is identical to that of other vaccines: our immune system generates a response by recognizing the proteins as foreign and developing antibodies against them. “
One problem for many countries is that they still cannot make mRNA vaccines.
For example, the Australian government has a deal for ten million doses of the BioNTech / Pfizer vaccine. Since this vaccine requires two doses, this agreement is enough for five million Australians. It’s unclear how long it will take for a vaccine to become widely available, but we may hear more about this in the weeks and months to come.
The vaccine requires storage at a temperature below -60 ℃. This will undoubtedly be a challenge for transportation and distribution , although not an impossible one. One solution to this problem is to establish vaccination centers to implement the vaccine once it is available. At a Pfizer briefing, the company said it will use ultra-low temperature shipping strategies and that the vaccine can be delivered on “dry ice.”
Harry Al-Wassiti, Bioengineer and Research Fellow, Monash University; Colin Pouton, Professor of Pharmaceutical Biology, Monash University y Kylie Quinn, Vice-Chancellor’s Research Fellow, School of Health and Biomedical Sciences, RMIT University
Este artículo fue publicado originalmente en The Conversation. Lea el original.
