VIVA – Pfizer and BioNTech have just released interim results from the Corona COVID-19 vaccine trial. Although it is not the only vaccine, this test has given enthusiasm to the whole world.
From the site Science Alert, Sunday, November 15 2020, it is not easy to know how effective a given is Corona vaccine. First, researchers need to find out if just injecting helps. Trials can involve large numbers of people, with half of the participants getting the vaccine, and half being given a placebo.
Read: A Husband and Wife Scientist Couple Successfully Created the First Coronavirus Vaccine
Then, they will get the infection and hopefully the vaccine can protect them. In some cases, such as HIV or Ebola, giving a placebo ethically is controversial because it has a high mortality rate.
As for COVID-19, researchers rely on natural infections because none of the researchers intentionally exposed the virus to participants. The Pfizer / BioNTech trial involved 44 thousand participants with 21,999 who were given the Corona vaccine.
Researchers used statistical analysis to find out whether the vaccine worked or not as cases increased. If the number of cases was small, it would not be clear whether the difference was between the placebo and the vaccinated group.
Statisticians use power analysis to find out how many cases need to be observed. For the Pfizer / BioNTech vaccine the target was 164 cases to estimate vaccine efficacy.
But the assumption of effectiveness is only 60 percent. There were 94 cases reported and 86 cases in the placebo group. The percentage of efficacy among the vaccinated group was up to 90 percent.
Although the number of cases is relatively small, statistical analysis allows researchers to predict what will happen if the Corona vaccine is launched. The trials included different ages as well as participants who came from different ethnicities.
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