Around 200 COVID-19 vaccine candidates worldwide are conducting clinical trials in phases 1 to 3; One or more of them aims to protect a large part of the population against the coronavirus pandemic that has devastated the world in 2020. However, some are leading. Pfizer has also announced high effectiveness rates; However, this vaccine candidate poses some challenges.
Moderna has not been slow to do the same. This Monday, November 16, he announced that the phase 3 study met the statistical criteria with a vaccine efficacy of 94.5% : “Moderna intends to request an emergency use authorization (USA) with the FDA ( Food and Drug Administration) in the coming weeks, “as can be read in a press release.
The reactions of the experts have not been long in coming, and have been collected by the Science Media Center portal, which guarantees scientific opinions without conflicts of interest.
Of the many ways in which a vaccine can be made, Moderna’s is made from nucleic acids, that is, the genetic material of the virus; in this case, RNA. The Pfizer / BioNTech vaccine introduced last week and Moderna’s are very similar in design, both with interim results also very similar. For Eleanor Riley, professor of immunology and infectious diseases at the University of Edinburgh: “The fact that two independent trials are giving very similar results is very reassuring.”
What can we expect from Moderna’s vaccine? What differences do you have compared to the Pfizer candidate?
Conservation
Both are RNA vaccines, which have the disadvantage that they must be stored at a very low temperature, below zero degrees Celsius (0ºC), which makes their transport difficult to various countries.
However, Moderna’s candidate vaccine is stable at –20ºC, compared to -70ºC for the BioNTech / Pfizer candidate vaccine. As Dr Zoltán Kis, Research Associate at Imperial College London, explains: “Once approved by regulatory authorities, Moderna’s vaccine could be distributed substantially easier compared to the BioNTech / Pfizer vaccine,” explains Zoltán Kis. .
In addition, Moderna has also announced that the vaccine can be stored in a conventional freezer for up to 6 months and that, once the vaccine is thawed, it can be stored for up to 30 days in a standard refrigerator (2 to 8ºC). This makes the vaccine much easier to administer.
“The data on the stability of the vaccine suggest that, although it requires a good freezer during the six months of the complete life of the vaccine, a common refrigerator seems adequate for a month, and will remain stable at room temperature for up to 12 hours,” notes the Professor of Pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, Stephen Evans.
Costs and production
On the other hand, the BioNTech / Pfizer vaccine could have lower costs, and also be produced in a higher proportion. The reason is the number of micrograms per dose : “Moderna’s vaccine candidate has a higher amount of mRNA per dose (100 micrograms per dose) compared to the BioNTech / Pfizer vaccine (30 micrograms of RNA per dose). The latter can be produced in a substantially higher number of doses compared to the Moderna vaccine when the same scale / size of RNA production process is used. Furthermore, due to the lower quantity per dose, the production cost per dose of the BioNTech / Pfizer vaccine will also be lower compared to the Moderna vaccine, ”he explains.
Effectiveness
The prerequisite for a COVID-19 vaccine is that it prevents people from getting sick enough to require hospital treatment and prevents people from dying. For Eleanor Riley, both vaccines seem like good candidates for this : “The preliminary data reported here suggests that this vaccine – and, by extension, the Pfizer / BioNtech vaccine – will achieve this goal.”
The Moderna press release refers to a study of 30,000 American adults, including many older or high-risk people. According to the Professor of Experimental Medicine at Imperial College London, Peter Openshaw: “This gives us confidence that the results are relevant in people with a higher risk of covid-19 and with a greater need for vaccines.”
On the other hand, the efficacy shown by the Moderna and Pfizer / BioNTech vaccines has been found to be above 85%, which would be what most scientists would have expected.
According to Trudie Lang, director of the Oxford University Global Health Network: “This is the first study to report severe cases and, although uncertainty remains, the finding that there were no severe cases with the vaccine and 11 cases with Placebo is very strong proof that the vaccine prevents both severe and mild disease. Compelling evidence regarding deaths is likely only when the vaccine is in use. “
Safety
The safety data also looks promising. According to Professor Evans: “A wide range of people with illnesses and minority groups, as well as a considerable number of older patients, were included in the trials. We will need a lot more data and a full report or publication to see if the benefit is consistent across all groups, especially the elderly, but this is definitely encouraging progress . “
Side effects
In terms of side effects, the news is pretty good too. The reported adverse effects, according to experts, are not surprising, and are typical of almost any vaccine. They are rarely long-lasting or serious.
Peter Openshaw, Professor of Experimental Medicine at Imperial College London, is quite optimistic about this: “The first dose caused pain at the injection site in about 3% of people; the second dose was associated with transient generalized symptoms in approximately 10% of people with fatigue, muscle aches, and flu-like symptoms. These effects are what we would expect with a vaccine that works and induces a good immune response ”.
Challenges
Professor Riley also points out some unknowns that still need to be answered. For example, if this vaccine, or any of those currently in trials, prevents disease transmission. “Vaccines that prevent symptomatic disease are likely to reduce the duration and level of infectivity and therefore reduce transmission, but we do not yet know if this effect will be large enough to make a significant difference in the spread of the disease. virus, “he explains.
However, all the experts point to the announcement as excellent news. “Having more than one source of an effective vaccine will increase the global supply and hopefully help us all return to something close to normal sometime in 2021,” recalls Riley.
“ What we still don’t know is how long protective immunity can last. For that, we will have to wait ”, he concludes.
