Because we need different vaccines against Covid-19

Because we need different vaccines against Covid-19

They have different efficacy, are stored differently, and may also have different administration schedules. The benefits of having multiple vaccines

(Photo: Mufid Majnun on Unsplash) We have begun to become quite familiar with vaccines. Enough to know that there are several. Currently three are approved: that of Pfizer / BionTech, that of Moderna and that of AstraZeneca, the latest arrival (among a thousand open questions). We also know that others will probably come in the future, not without controversy and among a thousand uncertainties. On the other hand, the reference document on the subject of the World Health Organization speaks of over 200 vaccines in development, counting both the preclinical and clinical ones. A 60in the latter, however many, many.

If it is true that now with the arrival of the first effective vaccines discussions are opening up - even ethical ones, as shown for example with the case of the Italian Spallanzani-Reithera vaccine and even before the publication of the efficacy results of the first products - on the usefulness and feasibility of further experiments, on the other hand having several available means being able to count on a varied armamentarium, which can prove useful in different contexts and for different purposes.

The publication confirming the incredible efficacy of the COVID-19 vaccine is fantastic news, but which opens up scenarios that are not easy to solve. Now there is the ethical problem relating to the continuation of the double-blind trials of the vaccine.

- Roberto Burioni (@RobertoBurioni) December 11, 2020

A dose of vaccine

For example, the arrival of vaccines that can provide protection after a single dose could also be of great help in vaccination campaigns. The question of dose administration has been at the center of a major debate, especially following the UK's choice to vaccinate as many people as possible with a single dose of a vaccine designed to provide protection after two doses, such as Pfizer / BioNTech and AstraZeneca. We now return to talk with the dissemination of the Johnson & Johnson vaccine results from the Ensemble study, which suggest an average protection of 66% after a single administration with their product, at 28 days (the J&J vaccine is of the type a viral vector). The protection - intended against moderate to severe forms of the disease - was however quite variable from area to area, higher in the US for example, and lower in South Africa, where most Covid-19 cases were due to infections with the variant. initially identified there.

These data are still provisional, but welcomed by many parties with enthusiasm, considering that, in the face of a protection for now comparable, for example, to that of the AstraZeneca vaccine (which is around 60 %), for the J&J vaccine we talk about a single dose (doubts remain about the effectiveness of the single with AstraZeneca, as explained by Enrico Bucci in Il Foglio). A fact that should not be underestimated, which could greatly simplify the administration of the vaccine, as reiterated by several parties and as reasonable to expect (just think of the organization of the recalls and the storage of second doses). Even if things could change for J&J too: as Nature recalls, in fact, the company is also carrying out a second trial (Ensemble 2), with the administration of two doses fifty days apart. Meanwhile, Johnson & Johnson has asked the US Food & Drug Administration for approval to enter the market.


The J&J vaccine can be maintained without particular technological requirements, at minus twenty degrees for two years and up to three months at temperatures between 2 ° C and 8 ° C, ensure from the company. The possibility of storing medicines with relative ease at traditional refrigerator temperatures - something common also to the AstraZeneca vaccine - is another aspect that can contribute to making a product more manageable, especially by general practitioners themselves. In fact, the storage of mRNA vaccines is more complex, especially for Pfizer vaccines (which must be stored at around -80 ° C and can resist in a classic fridge for a few days). If the ideal would be to have vaccines completely independent from the cold chain write Timothy Ford and Charles Schweik on the pages of The Conversation, to really take them to the poorest and most difficult to reach places, the simplification of conservation processes, at reduced cost and reduced technologies , is already something.


Besides the unexpected effectiveness of the first mRna vaccines, these products are particularly interesting also for their flexibility. That is, as experts have repeatedly repeated, they are easily adaptable platforms, by their very nature: in theory, when the virus changes, they can be easily reprogrammed by synthetically creating an mRna that takes into account the mutations of the virus. In theory, BioNTech claimed, it would take just over a month to create a new vaccine if necessary.

Differentiate the offer

It is a necessary need especially in times of vaccine shortage. a problem that is being tried to remedy also through the participation of the production sites of other pharmaceutical companies, such as Sanofi and Novartis. Having more vaccines today, with different efficacy profiles, different studies that have allowed their approval, also allows diversification of the offer. The Technical Scientific Commission of AIFA has also clearly reiterated this recently, specifying how, at present, it would be preferable to reserve the most effective vaccines (those with mRna) for elderly people or at higher risk of developing serious disease. For the AstraZeneca vaccine, on the other hand, the recommendation is for the population between 18 and 55 years old, but, as specified, without excluding those over 55 completely if healthy. Indications, those from Aifa, which also reported to review the vaccination plan.

Furthermore, counting (and betting) on ​​multiple products allows you not to depend on a single company, distributing the production load of vaccines and - hopefully - not to run out if problems arise with one.

And last but not least: all these considerations must be brought into reality, which as we have seen is subject to continuous variables that are only partially predictable. There are ideal conditions - very effective vaccines for everyone - real conditions exist - few vaccines, of different efficacy, of which to optimize their use - and for this reason the "alternatives" we have must be considered, he recalled in recent days, among others. infectious disease specialist Massimo Galli of the Sacco hospital in Milan. The meaning, after all, of the recommendations of the Aifa Commission.

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