Coronavirus vaccine Novavax (NVX-CoV2373)
Maximilian Reindl studied chemistry and biochemistry at the LMU in Munich and has been a member of the editorial team since December 2020. He will familiarize himself with medical, scientific and health policy topics for you in order to make them understandable and comprehensible.
More posts by Maximilian Reindl All content is checked by medical journalists.The Covid-19 vaccine from the manufacturer Novavax differs from the previously approved vaccines. Unlike these, it is not based on a genetic principle of action, but is based on the direct administration of artificially produced surface proteins of the virus - a process that is already known from other vaccines. The European Medicines Commission (EMA) is currently examining the data in a rolling review process - an early approval in Europe seems likely. Here you can find out what is known about the Novavax vaccine so far.
What kind of vaccine is it?
NVX-CoV2373 from the manufacturer Novavax is a so-called protein-based vaccine against the pathogen Sars-CoV-2. Vaccines of this type are also known as protein subunit vaccines.
In contrast to the previously approved genetic vaccines from the manufacturers BioNTech / Pfizer, Moderna, AstraZeneca and Johnson & Johnson, the central active ingredient in a protein-based vaccine is the (artificially produced) spike protein itself.
This artificial spike protein is mixed with an active enhancer - a so-called adjuvant. Adjuvants are substances that activate the innate immune system. They support the immune system in recognizing important structures of the pathogen in the future.
Differences between genetic vaccines and Novavax
The two main differences between the protein-based vaccine manufactured by Novavax and genetic vaccines are:
Direct administration of the spike protein: When NVX-CoV2373 is vaccinated, the “finished” spike protein, which has been pre-produced in the laboratory, is administered. This means that no genetic blueprint (as is the case with genetic vaccines) in the form of mRNA or vector viruses has to be smuggled into the body - or the human cell - in order to trigger an immune reaction against Sars-CoV-2.
Instead, Novavax produces the spike protein in special insect cells (Sf-9 cells) in the laboratory. The desired antigen is then isolated in large quantities, purified and processed into a “virus-like nanoparticle”.
This means that the manufacturer combines 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 set for an immune response: Individual protein nanoparticles are usually not enough to trigger an adequate immune response in the body. The immune system usually does not classify such structures as foreign. The human immune system must therefore first be made "aware" of NVX-CoV2373.
As mentioned above, this is achieved through the use of adjuvants. These substances stimulate the immune system and “lure” specialized cells of the (innate) immune system into the area of the puncture site. The increased number of specialized immune cells then - to put it simply - initiates the process of the adaptive (“learned”) immune response.
Adjuvants act as an "alarm signal" for our body's own pathogen defense. This principle of action - the combination of protein antigens combined with an adjuvant - has long been tried and tested.
The vaccines against tetanus, polio, diphtheria and whooping cough, which have been tried and tested for many years, also use “potentiators”. Other vaccine designs - such as the genetic vaccines from the manufacturers BioNTech / Pfizer, Moderna, AstraZeneca and Johnson & Johnson - can dispense with adjuvants entirely.
Effectiveness against Covid-19
A final evaluation by the European Medicines Agency (EMA) is still pending. Particular attention in the assessment is directed to the so-called PREVENT-19 study, which took place at 119 test centers in the USA and Mexico. A total of around 30,000 people between the ages of 18 and 84 took part in the study.
The study program indicates that the vaccine NVX-CoV2373 protects very well against moderate and severe courses. However, there is no reliable data on the very contagious delta variant, which is now also dominant in Europe.
Compared to the original wild-type coronavirus, the effectiveness is said to be the highest, followed by a slightly reduced effectiveness compared to the alpha variant (B.1.1.7) and a moderately reduced effectiveness against beta (B.1.351).
Tolerability and side effects
The data available so far indicate that NVX-CoV2373 is well tolerated. Side effects were rare in the PREVENT-19 study. These included the typical vaccine reactions such as pain at the injection site, exhaustion, headache and muscle pain.
These local and systemic vaccination reactions occurred only temporarily and usually subsided completely within a few days.
Information on very rare side effects
Further statements on safety and possible very rare side effects cannot be made at the moment. In the event of market approval, the Paul Ehrlich Institute (PEI) will continuously, closely and transparently monitor safety.
Combined flu and corona vaccine
Another previously published study examined an important aspect: Is a combined administration of the coronavirus vaccine NVX-CoV2373 with a seasonal flu vaccine possible and effective?
Apparently yes. The immunological data collected on around 400 people indicate that both vaccination protection against the coronavirus and protection against seasonal flu are created through a combined administration of both vaccines. However, participants reported stronger vaccine reactions.
For the time being it is a feasibility study ("Proof-of-Concept"). Because the small number of participants - and the sometimes very young age of those vaccinated - cannot yet be transferred to the general population. If you want to be vaccinated against both the coronavirus and the seasonal flu (influenza) in the coming autumn, it is best to discuss this with your doctor.
How is the Novavax vaccine used?
The vaccine NVX-CoV2373 is injected into the muscle of the upper arm. A series of vaccinations consists of two doses of vaccine given 21 days apart.
A vaccine dose itself consists of 5 micrograms of the recombinant spike protein nanoparticle, which is administered with an additional 50 micrograms of the saponin-based adjuvant (Matrix-M).
The vaccine can be used directly without prior dilution by local doctors. The preparation can be stored at temperatures of 2 to 8 degrees Celsius.
procurement
The European Commission (EC) negotiated a contractual acceptance guarantee with the manufacturer Novavax on August 4th, 2021. This framework agreement secures the EU states up to 100 million doses of the vaccine in a first tranche. It is not yet known how large the respective quotas will be for the individual EU countries.
There is also an option to receive an additional 100 million doses in the coming years 2022 and 2023, provided the EMA grants marketing authorization for the vaccine.
How does the rolling review process work in the EU?
The vaccine NVX-CoV2373 is currently still in a so-called rolling review process. The European Medicines Agency (EMA) has already successfully applied such an “ongoing” assessment procedure to the other four genetic coronavirus vaccines.
A rolling review process enables both sides - that is, the drug authority as well as the manufacturer - to make the approval process more flexible in terms of time in exceptional cases. This means that further results from ongoing clinical studies can be incorporated into the evaluation process that has already started. If sufficient data on efficacy, safety and immunogenicity are available, the manufacturer can then submit an official application for approval. This more flexible handling of the internal deadlines speeds up the approval process by a few months.
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