What kind of vaccine is Novavax?
The vaccine of the US manufacturer Novavax (Nuvaxovid, NVX-CoV2373) is a protein-based vaccine against the pathogen Sars-CoV-2. Nuvaxovid is an alternative to the mRNA vaccines of the manufacturers BioNTech/Pfizer and Moderna. On December 20, 2021, the European Medicines Agency (EMA) granted a (conditional) marketing authorization for Europe.
Unlike those, in a protein-based vaccine the key active ingredient is the (artificially produced) spike protein itself – not its genetic blueprint. Nuvaxovid therefore belongs to the class of semisynthetic protein subunit vaccines. The artificial spike protein is mixed with an effect enhancer (adjuvant). Adjuvants are substances that activate the innate immune system. Such substances help the immune system to learn important structures of the pathogen in order to recognize them in the future.
How is Novavax vaccinated?
According to the registration documents, a regular vaccination series with Nuvaxovid consists of two vaccine doses to be administered at a time interval of 21 days. The vaccine itself is injected into the upper arm muscle.
Currently not an option as a booster
Nuvaxovid is not currently approved for booster vaccination or as a booster option. This means that third party vaccinations with Nuvaxovid can currently only be given in exceptional cases. For example, if there are incompatibilities with the ingredients of mRNA vaccines.
The reason for this is that the manufacturer Novavax has not applied to the European Medicines Agency for use as a booster – although Nuvaxovid would presumably be suitable for this purpose.
Which booster after Novavax basic immunization?
If you have undergone basic immunization with the Novavax vaccine with two doses, STIKO recommends the regular mRNA boosters.
Pregnancy and lactation
However, if you have received a Nuvaxovid vaccine in an undiagnosed pregnancy, this is not a cause for concern.
Efficacy against Covid-19
The EMA paid particular attention to the so-called PREVENT-19 study, which took place at 119 testing centers in the United States and Mexico. A total of about 30,000 people between the ages of 18 and 84 participated in the study. The study program indicates that the vaccine NVX-CoV2373 provides very good protection against severe covid-19 disease.
The pivotal studies found that nuvaxovid showed the highest efficacy against the original wild-type coronavirus – followed by slightly reduced efficacy against the alpha variant (B.1.1.7) and moderately reduced efficacy against beta (B.1.351).
How well nuvaxovide also works against the currently predominant omicron variant – and in particular against omicron subtype BA.5 – is currently unclear.
Tolerability and side effects
Information on rare side effects
Since market approval, the Paul Ehrlich Institute (PEI) has continuously and closely monitored safety.
However, conclusive statements on safety as well as on possible very rare side effects cannot be made at present – the total number of doses administered remains manageable. First further surveys on safety are based on the evaluation of about 121,000 vaccine doses administered as of the cut-off date of 27.05.2022 in Germany. Since the introduction of the vaccine, the PEI has received a total of 696 suspected cases of adverse reactions.
This corresponds to a reporting rate of 58 suspected cases per 10,000 vaccinations – or, in other words, about 1 suspected case of adverse reaction per 172 vaccinations. The majority of these reports were transient and not serious. Women were overrepresented in the adverse reaction reports received by a ratio of two to one.
Transient vaccination reactions predominate
- Headache
- Fatigue and tiredness
- Pain at the injection site
- Dizziness
- Chills and febrile reactions, as well as
- Malaise, aching limbs, muscle aches and other mild reactions.
However, in total, 42 patients also experienced serious adverse reactions that required hospital care. In two percent of all reported cases, adverse reactions persisted during the period considered. However, the risk of myocarditis and pericarditis was not increased during the observation period – although three suspected cases were reported. Deaths temporally related to nuvaxovide vaccination did not occur.
Differences between genetic vaccines and nuvaxovide.
The two most important differences between the protein-based vaccine from the manufacturer Novavax and genetic vaccines are:
Instead, Novavax produces the spike protein in special insect cells (Sf-9 cells) in the laboratory. The desired antigen is then isolated in larger quantities, purified and further processed into a virus-like nanoparticle.
This means that the manufacturer assembles several copies of the spike protein molecule into an artificial particle – around 50 nanometers in size. In this way, the outer shell of the coronavirus is mimicked.
An additional stimulus must be provided for an immune response: Single protein nanoparticles are usually not sufficient to trigger a sufficient immune response from the body. The immune system does not usually classify such structures as foreign to the body. The human immune system must therefore first be made “aware” of NVX-CoV2373.
Adjuvants act as an “alarm signal” for our body’s own pathogen defenses. This principle of action – i.e. the combination of protein antigens combined with an adjuvant – has been tried and tested for a long time.
The long-established vaccines against tetanus, polio, diphtheria or pertussis also use “effect boosters”. Other vaccine designs – such as the genetic vaccines from manufacturers BioNTech/Pfizer, Moderna, AstraZeneca and Johnson & Johnson – can do without adjuvants entirely.
A vaccine dose consists of two different ingredients: 5 micrograms of the recombinant spike protein nanoparticle combined with an additional 50 micrograms of the saponin-based adjuvant (Matrix-M).
