The World Health Organization’s (WHO) Strategic Advisory Group of Experts (SAGE) has recommended Valneva’s COVID-19 vaccine – VLA2001 for all individuals aged 18 to 50 years old.
The vaccine is not recommended for people aged 50 years and avoid, due to limited data on the immunogenicity of the vaccine in this age group. Similarly, there is no data on efficacy or safety for people below the age of 18 years, and vaccination of this age group is therefore not currently recommended.
VLA2001 is a purified, inactivated and adjuvanted whole virus SARS-CoV-2 vaccine, employing a similar approach to the flu vaccine.
Following administration of VLA2001, the spike protein of SARS-CoV-2 and other viral surface antigens, stimulate both neutralising and other functional binding antibodies, as well as cellular immune responses directed against the spike and other surface proteins, which are thought to contribute to protection against COVID-19.
The recommendation is supported by a pivotal clinical immunogenicity study, which demonstrated that people 30 years and older who received VLA2001 produced more neutralising antibodies and had about the same seroconversion as people who received the Oxford/AstraZeneca recombinant COVID-19 vaccine – ChAdOx1-S – following two doses of the vaccine. People aged 18 to 29 years old who received Valneva produced even more neutralising antibodies, following two doses of the vaccine.
WHO notes that there is no vaccine efficacy data available from this trial – only on immunogenicity – as it is no longer considered ethical to ask a group of people to remain unvaccinated for participation in efficacy trials.
The interim guidance, which was developed on the basis of the advice issued by SAGE on immunisation at its plenary meeting on 11 August 2022, recommends the primary vaccine series is two doses – 0.5ml each dose – given intramuscularly. The second dose is recommended to be administered at least 28 days after the first dose.
WHO also recommended the use of a second booster dose for individuals at high risk of severe disease, administered four to six months after completion of the primary series.
WHO outlined that studies are ongoing to assess the ability of VLA2001 to neutralise variants of the SARS-CoV-2 virus. Initial results are available and indicate that the Valneva vaccine produces fewer neutralising antibodies against the Delta and Omicron variants, indicating it provides less protection against these variants.