The adapted Omicron boosters for the sub-variants BA.1 and also for BA.4/BA.5 are now approved in the EU. On what basis the decision is based and which vaccine is better.
In the USA, an adapted corona vaccine for the Omikron sublines BA.4 and BA.5 received emergency approval on August 31st. The European Commission has now also approved the vaccine from the manufacturer Biontech/Pfizer that has been adapted to the Omikron sublines BA.4 and BA.5 (September 12, 2022). What does that mean?
The European Medicines Agency (EMA) had previously recommended approval of the vaccine for people aged 12 and over. Federal Health Minister Karl Lauterbach told the “Handelsblatt” that the adapted BA.4/BA.5 vaccine should be delivered in Germany next week. It is a bivalent vaccine. It means that the vaccine contains molecules to make the spike protein of the original coronavirus and the omicron subvariants BA.4/BA.5. The virus needs the spike protein to enter the body’s cells.
BA.4/BA.5 vaccine should provide better protection
In contrast to the original variant of the coronavirus, the omicron variants have some mutations in the spike protein – this is how the virus manages to bypass the body’s immunity to the original coronavirus. “The bivalent vaccines aim to provide broader immunization against Covid-19,” said Biontech Green Uğur Şahin in a company statement.
The EU had only recently approved two other adapted Omicron vaccines. These were also bivalent vaccines from the manufacturers Biontech/Pfizer and Moderna. They are adapted to the omicron subvariant BA.1. But this variant no longer plays a role in the infection process in this country. According to the current weekly report from the Robert Koch Institute, 96 percent of infections can be attributed to BA.5. A very small proportion has been triggered by subtypes BA.2 and BA.4.
The purpose of bivalent vaccines
The reason why the adapted vaccines contain both the blueprint for the omicron subtypes BA.1 or BA.4/BA.5 and the wild type is that better protection is expected in this way. Because: At the moment the omicron subtype BA.5 dominates in Germany, but the corona virus has changed many times in the past and nobody knows what future Covid 19 variants will look like. Theoretically, it is conceivable that new variants will emerge whose spike protein is more similar to that of the wild type than the omicron subtypes BA.1 and BA.4/BA.5.
The EMA informs that the adapted vaccines work in the same way as the original Corona vaccine. The body is given the blueprint to produce antibodies against the original coronavirus or the omicron subtypes BA.1 or BA.4/BA.5. If the body later comes into contact with the virus, the immune system recognizes the pathogen and can attack quickly and specifically. The mRNA molecules from the vaccines do not remain in the body but are broken down shortly after vaccination.
Two omicron boosters are approved in Europe (two vaccines adapted to BA.1 and one to BA.4/BA.5). So which vaccine is better? Uğur Şahin said in an interview with “Spiegel”: “Basically, there is no huge difference between the two vaccines. Both have shown in studies that they produce a clearly superior antibody response to Omicron compared to the original vaccine. At the same time, we have clear indications that a BA.5 vaccine works even better against BA.5. But there are also opinions that in a few months a variant that is closer to BA.1 again could emerge.”
Efficacy of a fourth injection of omicron booster
In the clinical study by the manufacturer Biontech/Pfizer with over 1200 subjects who had already received primary immunization and received various boosters in the study, it was shown that the adapted bivalent BA.1 vaccine compared to the previous vaccine to a ninefold higher neutralization of omicron variant coronaviruses. Even though the vaccine is optimized for the omicron subvariant BA.1, it protects against infection with BA.4/BA.5 better than the original vaccine: It shows a four-fold improved effect against the variants BA.4 and BA.5 – compared to an unadapted vaccine.
Vaccination with an adapted Omicron vaccine can increase protection against infection – but it is also not a silver bullet. It pushes, so to speak, the previous protection that was already built up by the previous corona vaccinations. “The adapted vaccines are not a new kind of supershield compared to the vaccines you’ve had before,” John Moore, a vaccines expert at Weill Cornell Medicine in New York, told Nature.
Even if the omicron variant usually causes mild courses, vaccinations are important to protect against serious illnesses and/or treatment in hospital. A study from the USA compared data from 13 US states from January 2021 to April 2022. The researchers wanted to find out how high the risk is for adults over the age of 18 to have to be treated in hospital with an omicron infection and what role the vaccination status plays in this.
The result: Unvaccinated people were hospitalized 10.5 times more often than people who had received two vaccinations. The booster also plays a role: people who have been vaccinated twice had to be hospitalized 2.5 times more often than people who had been boosted. At the time of the study, no vaccine adapted to Omicron had been approved in the USA either.
Recommendation of the Stiko is still pending
There is not yet a recommendation from the Standing Vaccination Commission (Stiko) for the adapted Omikron vaccines. Federal Minister of Health Karl Lauterbach wrote on Twitter that Stiko is already working on new recommendations.
So far, the committee recommends a second booster for everyone over the age of 60. Stiko also recommends the renewed booster with the original corona vaccine for people aged five and over who have an increased risk of serious illnesses. The vaccination should be administered no earlier than six months after the last vaccination or after recovering from a Covid-19 infection.
Basis of approval for adapted Omicron vaccines
The basis for approval of the vaccines adapted to BA.1 and BA.4/BA.5 are slightly different from each other. For approval with the BA.1 vaccine from Biontech/Pfizer and that from Moderna, the EMA justifies its approval recommendation with the results of the clinical studies on humans from the two manufacturers.
For the BA.4/BA.5 adapted vaccines, the authority bases its approval recommendation on the clinical studies for the BA.1 vaccines and on laboratory and animal tests for the adapted BA.4/BA.5 vaccine. A clinical trial for Biontech/Pfizer’s adapted BA.4/BA.5 vaccine began in early September and results are expected to be available this fall.
EMA said: “Apart from containing mRNA derived from different but closely related omicron sublineages, the adapted bivalent BA.1 vaccine and the BA.4/BA.5 vaccine have the same composition. “
Emergency admission in the US in late August
Also in the US, the emergency use approval of the Omicron BA.4/BA.5 adapted vaccines is based on clinical trial data on the BA.1 adapted vaccine, data on the millions of people who have already received a Covid-19 vaccination and who have not -clinical data for BA.4/BA.5 boosters, FDA chief Robert Califf wrote on Twitter in August.
There was also criticism of the emergency approval in the USA without data on humans. The FDA’s decision was based, among other things, on an animal study. A total of 32 mice were divided into four groups of eight each. Depending on the group, they were given the original corona vaccine, the bivalent vaccine adapted to BA.4/BA.5, the vaccine adapted only to the omicron variant BA.1 and the vaccine adapted only to the omicron variant BA4/BA5. In this study, it could be demonstrated that the BA.4/BA.5 adapted vaccine as a booster in animals shows an increased immune response in contrast to the original Covid-19 vaccine.
Known procedure of flu vaccinations
The question of whether corona vaccines adapted to variants should only be approved after new clinical studies have been carried out has been discussed among vaccination experts for a long time.
Because: It is a risk assessment – if clinical data is required for the approval of the adapted vaccines, it will take longer for the vaccines to be available on the market. The result could be that another variant is already dominant by the time it is approved. Biologist Ulrich Elling said on this question in an interview with the star: “Without an optimally adapted vaccine, there will be more cases of illness and thus more severe courses and deaths.”
The procedure that adapted vaccines are approved without new extensive testing is common with modified flu vaccines, as Ulrich Elling explained. Immunologist Carsten Watzl also said in an interview with the Science Media Center that the annually adapted flu vaccine is not yet being tested in human studies.
Sources: , , , , , , , , , , , , ,
Source: Stern
