The US pharmaceutical company Pfizer, in collaboration with the German medical research firm BioNTech, announced yesterday that current vaccine trials for COVID-19 had reached a milestone in the form of a preliminary efficacy rate of 90%.
This is good news, but based on what we know so far it is too early to start celebrating.
Let's see what you need to know.
Pfizer, in a press release, claims a 90% reduction in COVID-19 symptom cases between those who received the vaccine compared with those who received a placebo. These are preliminary results of the phase three vaccine trial.
During the third phase of vaccine testing, the pharmaceutical industry focuses on both determining the efficacy and safety of a vaccine so that explicit data can be presented to the various global and national bodies responsible for its approval. drug.
If the vaccine is effective and relatively safe (given that drugs such as Remdesivir were discontinued as treatments for COVID-19 in the third phase by most researchers after discovering possible fatal comorbidities), it will be approved for distribution.
The very good news should not be construed as a statement that the vaccine is 90% effective in preventing COVID-19 infections in the general public. There is currently no evidence that the vaccine will be effective in cases of high maternal load, or in patients with symptoms severe enough to require hospitalization.
In addition, Pfizer has not disclosed data to the public and this research has not been evaluated by peer companies. Everything we know comes from a press release. We need to keep our tones low until we really see the company data - and have the experts check it.
However, even if we assume that the numbers and claims in the press release published by Pfizer are correct, this does not mean that the battle has been won. Pfizer is very optimistic, it has already started manufacturing the vaccine. According to the company:
Based on current forecasts, we expect to produce up to 50 million doses of vaccine worldwide in 2020 and up to 1,3 billion doses in 2021.
The great idea behind vaccinating the public is to reach a turning point where so many people will have been vaccinated that the virus does not have enough viable hosts to continue to jump from person to person and eventually disappear. This is a form of herd immunity.
So how many doses must Pfizer produce for the vaccine to cause herd immunity? The answer depends on whether the vast majority of the world's population socially distances themselves, wears masks and washes their hands whenever they risk exposure.
We do not have any way of knowing the prospects for this particular virus, but we do know that the doses that Pfizer will produce will be enough to vaccinate about 9% of the world's population by 2022. To reach that number, we cut 1,3 billion doses in half, as Pfizer data show that patients will have more protection after the second dose.
A global vaccination rate of less than 10% will probably not be enough to establish any kind of herd immunity. According to the World Health Organization:
The percentage of individuals who must have antibodies to achieve herd immunity to a particular disease varies with each disease. For example, herd immunity to measles requires 95% of the population to be vaccinated. The remaining 5% will be protected as measles will not spread among those who have been vaccinated. For polio, the limit is around 80%.
This means that the Pfizer vaccine alone is unlikely to eradicate the virus or even significantly curve it in any substantial way for at least another year. About 91% of the Earth's inhabitants will probably not have access to the vaccine by 2022 at the earliest.
Of course the only way to slow down or stop the virus in 2021 is to convince the majority of the world's population to be vaccinated.
A vaccine that has not yet been evaluated by peers and will not be available to selected individuals for at least another year is not going to end the pandemic.
Wearing masks, washing our hands, increasing the number of examinations and following the guidance of the World Health Organization and other reputable medical institutions may be the only solution if we want to end this pandemic.