US pharmaceutical company Pfizer and German partner BioNTech have announced promising data for a COVID-19 vaccine that has entered late-stage clinical trials
In a press release on Monday, 9 November, the drugmakers raised hopes around the world when they announced that their mRNA-based vaccine candidate, BNT162b2, has demonstrated evidence against the infection caused by the novel coronavirus, SARS-CoV-2.
The announcement was, however, made based on a first interim efficacy analysis.
According to Al Jazeera, scientists and doctors around the world are still cautioning that many questions remain unanswered and celebrations may be premature.
1. Pfizer reported that the vaccine is 90% effective at preventing COVID-19 in early results
To produce an efficacy rate for the vaccine, an external and independent data monitoring committee (DMC) performed its first interim analysis after 94 participants in the 44,000-volunteer trial developed COVID-19.
It found that 90% of the people who received the vaccine were better protected from COVID-19 than the people who did not receive it (but had received placebos).
"Today is a great day for science and humanity. The first set of results from our Phase Three COVID-19 vaccine trial provides the initial evidence of our vaccine's ability to prevent COVID-19," said Dr Albert Bourla, chairman and chief executive officer (CEO) of Pfizer.
However, even Pfizer has said that as the study continues, the final vaccine efficacy percentage may vary.
2. The vaccine still has to complete Phase Three clinical trials and that data has to be submitted for scientific peer review before it can be considered for use in public
The Phase Three clinical trial of the vaccine began on 27 July and has enrolled 43,538 participants to date, 38,955 of whom have received a second dose of the vaccine, as of 8 November.
The clinical trial will continue until 164 volunteers develop COVID-19 - a number that the Food and Drug Administration (FDA) has agreed is enough to tell if the vaccine was working.
Researchers are including new study endpoints to characterise the vaccine's performance, such as in patients with severe COVID-19 disease or who had COVID-19 before.
Participants will also continue to be monitored for long-term protection, safety, and potential side effects for a total of two years after their second dose.
3. If approved, it will be the first mRNA vaccine ever to be in the market
According to Stat News, no mRNA product has ever been approved by regulators.
Different from conventional vaccines that usually use weakened or inactivated proteins of a virus, this vaccine will contain mRNA, a reversed genetic code of the virus, that will produce a protein to elicit an immune reaction from the body to attack it.
Thus, the vaccine will create antibodies that specially protect against COVID-19 infections, without producing the disease caused by the virus itself.
4. The vaccine has to be stored at ultra-low temperatures, which will present a logistics problem if approved
According to Reuters, wide distribution of the vaccine will be a challenge as it uses novel technology.
The synthetic mRNA vaccines need to be kept at -70°C and below. Otherwise, it would only last five days if kept at 2°C to 8°C - the temperature of normal refrigeration in hospitals.
It will get more complicated considering the vaccine's two-dose schedule.
5. Pfizer and BioNTech expects to produce up to 50 million vaccine doses this year if all goes well
They also expect to produce up to 1.3 billion doses globally in 2021.
So far, the companies have supply agreements with the US government, the European Union, the United Kingdom, Canada, and Japan.