This is how well Biontech, Moderna and AstraZeneca vaccines work

This is how well Biontech, Moderna and AstraZeneca vaccines work

Effective vaccines are the miracle solution to combat the corona pandemic, there is little doubt about it. Several vaccines have been developed, two of which, Comirnaty from Pfizer / Biontech and COVID-19 vaccine from Moderna, have already been approved in Switzerland. AstraZeneca’s third vaccine, which is still in the approval process, has already been approved in the EU.

The first results are cautiously optimistic: at least these vaccines prevent serious diseases. But what about preventing a SARS-CoV-2 infection and how high is the protection after the administration of a single dose of vaccine? Do vaccines also work against the British or South African mutant of the virus? We are investigating these questions here.

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Pfizer / Biontech Comirnaty

Type of vaccine

The BNT162b2 vaccine developed by Pfizer / Biontech and marketed under the name “Comirnaty” is one of the so-called mRNA vaccines. The mRNA is genetic information that contains the plane of the spike protein on the surface of the virus. It enters the cells of the body through small drops of fat, which causes them to produce the protein of the pathogen, which is harmless in itself. The body’s immune system reacts to this by forming antibodies against the virus protein; it is able to recognize the virus if it later comes into contact with it.

management

2 doses of 0.3 milliliters each at least 21 days apart, administered as an intramuscular injection in the upper arm. Approved for adults and young people from 16 years old.

effectiveness

In November 2020, Pfizer / Biontech announced the final results of its phase III study of BNT162b2 in a press release, according to which the vaccine provided 95 percent protection 28 days after the second dose was administered. This means that 95 percent fewer illnesses occurred among subjects in the vaccinated group than among those in the control group who received a placebo. The vaccine is said to be equally effective in both sexes and in all ethnic groups and in all age groups; effectiveness is more than 94 percent for people 65 and older.

The analysis also showed that protection already existed after the first dose: in the first 12 days after its administration, there were no significant differences with unvaccinated subjects, but after that the incidence was lower in vaccinated test subjects and protection was less than that of vaccinated subjects. second dose more than 52 percent. From 7 days after the second dose, the protection was already maximum.

Millions of people have already been vaccinated with BNT162b2. Preliminary results are encouraging: in Israel, where a third of the population has already been vaccinated, and exclusively with BNT162b2, the data indicates that the vaccine greatly reduces the number of symptomatic Covid-19 diseases even before the second dose.

A study by clinical infectologist Eyal Leshem and his team published in “The Lancet” shows that there was a 30 percent decrease in all SARS-CoV-2 infections in the first 14 days after the first dose. This reduction increased to 75 percent between 15 and 28 days after the first dose, while the number of symptomatic illnesses decreased by 85 percent. The results of the study could make it seem justified temporarily to waive a second dose in countries with a shortage of vaccines to vaccinate a larger part of the population with a single dose.

A large observational study conducted by the Israeli Ministry of Health, working with Pfizer / Biontech, is also cause for hope. The study, which has not yet been officially published, evaluated data from around 1.7 million people who had been vaccinated and concluded that the vaccine can prevent transmission of the virus by a good 89 percent, including asymptomatic cases.

Apparently, this protection also applies to the British mutant virus B.1.1.7, because it already dominated the cases examined in Israel with more than 80 percent. There is no information on protection against the South African or Brazilian mutant, as very few cases have been observed. However, laboratory tests published in the New England Journal of Medicine indicate that BNT162b2 is less effective against the South African mutant B.1.351. The neutralizing effect of the vaccine was reduced by two thirds. However, according to Biontech, it is still high enough to neutralize viruses.

According to more information from the Israeli Ministry of Health, after the administration of the second dose, the vaccine prevented 95.8 percent of Covid-19 disease, 98 percent the appearance of symptoms such as fever and breathing difficulties and about 99 percent of hospitalizations, serious illnesses. and death.

Moderna COVID-19 vaccine

Type of vaccine

Moderna’s mRNA-1273 vaccine, sold under the name “COVID-19 Vaccine Moderna,” is based, like Pfizer / Biontech’s, on mRNA smuggling modeled after the SARS-CoV- spike protein. 2 in the cells of the body and induce an immune response in the body.

management

2 doses of 0.5 milliliters each at least 28 days apart, administered as an intramuscular injection in the upper arm. Approved for adults 18 and over.

effectiveness

14 days after the second dose, mRNA-1273 achieved 94.1 percent protection in the phase III study, almost as good as the Pfizer / Biontech vaccine. In the group of 65 years or more, the Moderna vaccine was somewhat less effective, here the protection was only 86.4 percent; however, significantly fewer subjects were tested in this age group. The protective effect against Covid-19 began two weeks after the first dose; maximum efficacy was achieved one week after the second dose. The vaccine 100 percent prevented a serious illness from Covid 19.

According to a statement from Moderna, the vaccine was also effective against British and South African mutants when tested in vitro. However, the pharmaceutical company admitted that the vaccine fought the South African virus variant B.1.351 more slowly and less efficiently: the amount of antibodies against the virus was six times less. However, the level of neutralization of the antibodies is still above the threshold above which a protective effect is expected.

Moderna still wants to further improve the vaccine and test a variant with a design specifically designed for the South African mutant (mRNA-1273,351). Also, tests should show whether a third dose of vaccine could improve immunization. Moderna did not provide information on the time after the second dose that a third dose could be administered.

AstraZeneca vaccine

Type of vaccine

The ChAdOx1 nCoV-19 (AZD1222) vaccine from AstraZeneca, the trade name of which has not yet been determined, is the so-called vector virus vaccine. It is based on a chimpanzee adenovirus that cannot reproduce in human cells and that carries the genetic blueprint (DNA) of the virus’s spike protein to the cells of the body. The body then forms antibodies against the protein, which then act against the virus even in the event of contact with SARS-CoV-2.

management

2 doses of 0.5 milliliters each, 28 to 84 days apart, administered as an intramuscular injection in the upper arm. Approved for adults 18 and over.

effectiveness

According to the phase III study, AstraZeneca’s AZD1222 vaccine offers about 63 percent protection against symptomatic Covid 19 disease. Longer intervals between the two doses appear to increase efficacy. However, the 65+ age group made up just under ten percent of the test persons, and there were only 12 Covid-19 cases among them, so the protective effect of 52 percent determined for this group has a weak statistical base. .

In a series of tests with a small group of participants up to 55 years of age in phase III, test subjects received a half dose first and a full dose the second time. Here the protection was 90 percent. A study recently published in The Lancet, using data from AstraZeneca and the University of Oxford, also concluded that longer dosing intervals improved the effectiveness of the vaccine.

AZD1222 even appears to offer better protection against the risk of severe Covid 19 disease than the Pfizer / Biontech vaccine. This is suggested by a large observational study from Scotland looking at hospitalization for Covid-19. The study found that the AstraZeneca vaccine was 94 percent effective, while the Pfizer / Biontech vaccine was only 85 percent.

The AstraZeneca vaccine is being used on a large scale in the UK. It has been proven effective against the British mutant that dominates there. However, there are doubts as to whether this is also the case for the South African mutant. A South African study recently showed that the effectiveness against B.1.351 was only 10.4%. The vaccine offered little protection against mild and moderate cases of Covid-19. No clear statement on the effect against severe cases could be made, as the study was relatively small and mainly involved younger people with fairly mild disease courses. Although the World Health Organization recommends continued use of the vaccine, South African authorities have temporarily stopped vaccines with AZD1222.