Protein subunits and inactivated vaccines line up to join vaccination campaigns – EURACTIV.com

The EU appears to be comfortable betting on COVID mRNA vaccines for now. But just around the corner, vaccines developed under other platforms are lining up, with recombinant proteins and all vaccines inactivated by the virion in the lead.

There are currently four COVID vaccines authorized in the EU: MRNA vaccines such as Comirnaty or Spikevax, developed by Pfizer / BioNTech and Moderna respectively, and adenoviral vector vaccines – Vaxzevria from Oxford and the single injection vaccine Janssen by Johnson & Johnson.

The EU vaccination strategy relies heavily on mRNA vaccines. The Commission recently sign the world’s largest contract for COVID-19 vaccines contract with Pfizer / BioNTech, which projects the delivery of 1.8 billion doses of vaccine between the end of the year and 2023.

Contacted by EURACTIV, a European Commission The spokesperson explained that the focus should be on proven technologies and that mRNA vaccines are a clear example.

But vaccine developers are already working with new vaccine platforms.

The EU’s European Medicines Agency (EMA) is in contact with just over 30 developers of potential COVID-19 vaccines and is carrying out an ongoing review of four potential COVID-19 vaccines.

According to the World Health Organization landscape of candidate vaccine development, there are more than 100 vaccines in clinical development worldwide, dominated by protein-based subunit vaccines.

“The main types of vaccines that we will see later are these recombinant proteins and vaccines inactivated by the whole virion” Adam Finn from the European Technical Advisory Group of Experts on Immunization (ETAGE), which is also president of pediatrics at the University of Bristol, told EURACTIV.

These two platforms, he added, “are much more traditional” and could already enter vaccination campaigns in the coming months.

“There are many other more experimental platforms. And it is quite difficult to get information about it because very often the developers are quite secretive about what they are doing, ”said Finnish.

Protein-based subunit vaccines prepare for vaccination marathon

The Commission spokesperson said that the protein-based subunit vaccines were also recommended for use by scientific experts, in addition to mRNA vaccines.

These vaccines should be cheaper because they can be transported at higher temperatures than mRNA vaccines.

“It’s a very well established technology now. It has been around for about 30 years. The most prominent example of this technique is the hepatitis B vaccine, ”said ETAGE’s Finn.

“In principle, this should be a much easier and more direct way to manufacture vaccines than either of the new technologies where the bases of manufacture have to be set up from scratch,” he said. he declares. mentionned.

The lower price and large quantities, along with emerging evidence for their effectiveness, are expected to increase the popularity of this type of vaccine. Another factor is the safety of the new platforms used for COVID-19 vaccines.

“New security signals emerging, rare but serious, or potentially serious, with new platforms are interfering with the political will to use them,” Finn said..

The “Mix and match” could advance vaccination

These new COVID-19 vaccines could be those that join the “mix and match” or heterologous vaccination strategy already observed in some Member States.

In a joint update released on Wednesday (July 14), the EMA and the European Infectious Diseases Agency (ECDC) noted that the experts responsible for vaccination programs in more than half of the Member States have decided, taking into account their national circumstances, to use for the second dose vaccines different from those used for the first.

In the heterologous vaccination strategy, which has already been applied for some other vaccines, a different vaccine is given for the second dose in a recommended 2-dose schedule. This can allow for faster deployments of the vaccination strategy.

“Perhaps the most compelling reason for mixing and matching is that it gives you flexibility in terms of supply,” Finn explained, highlighting situations where health authorities have been. give a specific vaccine to the population and then stop receiving it.

While preliminary results from studies in Spain, Germany and the UK suggest a satisfactory immune response and few safety concerns, the EMA and ECDC still refrain from making a definitive recommendation to use different COVID-19 vaccines for the two doses.

In Finn’s opinion, using different vaccines is a “pretty good idea”.

“The upside is that there may be an advantage in presenting the same antigen to the immune system in a different way, in that it may stimulate a larger response or a larger response than using the same stroke. all the time, ”he said, adding, however, that it is not yet clear how these better responses turn into better protection.

[Edited by Zoran Radosavljevic]