The flu vaccine is mostly produced by a very archaic method: by replicating the virus in embryonated eggs from which it is then collected, inactivated and administered as a vaccine.
Now we also have other systems to produce it, but the substance does not change: it takes time. The flu vaccine is needed in October (so that vaccinated people are protected in December-January), but how do you know which virus will circulate in the months to come? Simple: it’s a guess. However, as Niels Bohr, Nobel laureate in physics said, making predictions is very difficult, especially about the future. And in fact the experts of the World Health Organization who in February choose the viruses (typically four strains) to be included in the vaccine to be administered in October sometimes guess, others not. When you guess the effectiveness is around 50-60%, but when you get it wrong it’s a disaster. For example, in the 2004-05 flu season the effectiveness was only 10%, and in 2014 it was 19%. In short, a big problem, considering that this variable effectiveness is compounded by the fact that the vaccine works particularly badly in the elderly, who are those who most need – being the most vulnerable – of solid protection.
Obviously, the development of an mRNA vaccine could radically change the cards on the table: as we have seen, it does not take months to design and produce this type of vaccine, but weeks, so the predictions could be much more accurate. . In addition to this, in the case of COVID-19, the protection was also excellent in older people. In short, it is to be hoped that soon a new, extremely more effective vaccine will be administered in October (perhaps together with the one against COVID-19, which could have a seasonality not too different from that of the flu), which is currently underway. of experimentation just as this book goes to print.
The vaccine against the flu is not that great, but at least it exists: for many infectious diseases the vaccine just doesn’t exist, and this is a problem.
Leaving aside HIV, the virus that causes AIDS and that you surely know (at the end of January 2022, phase 1 of an mRNA vaccine against HIV began), there are many viruses that are a significant problem from the point of view. from a medical point of view and against which there is no vaccination.
Respiratory syncytial virus (RSV), which we have already talked about, is a terrible killer of children (it is, globally, the second leading cause of mortality after malaria for children under one year of age). In addition to sending 3,400,000 a year to the hospital all over the world, filling the pediatric wards, it represents a very serious danger for newborns who have congenital problems, because in these small patients the consequences of RSV infection can be very serious. As mentioned, in the 1960s a vaccine was developed with catastrophic results: the vaccinated became more seriously ill than the unvaccinated. The hope that an mRNA vaccine may be able to provide effective protection to these particularly vulnerable babies is real and, even in this case, trials are underway.
Other insidious viruses are the herpes ones. They take their name from the Greek verb hérpein, which means “to crawl”. In fact, their characteristic is to infect the patient and remain latent in his organism for life. From time to time they awaken, without the patient noticing, and make it infectious. You got it right: each of us, right now and in perfect health, could be a vehicle for contagion for one of those viruses.
In this family, for example, we include the cytomegalovirus, which is not particularly dangerous for most people, but can have very serious consequences if it affects a pregnant woman or an immunosuppressed patient. In the first case, the infection can also seriously damage the fetus: if the potential source of the infection is every person in good health that the pregnant woman may encounter, it becomes very difficult to defend against an infection. In the case of immunosuppressed, the consequence can be even worse and, not infrequently, the clinical picture caused by the infection is a very serious problem for these patients. In short, we would very much like to get the cytomegalovirus off our feet: it is a pity that all attempts to produce a vaccine have failed miserably. But even in this case, mRNA vaccines are being tested, so let’s keep our fingers crossed.
The same is true of the Epstein-Barr virus, which is the cause of infectious mononucleosis. The patient becomes infected (typically as a boy, it is the “kissing disease” because it is transmitted very well with saliva), he heals but the virus remains latent inside the organism. Then – without the patient noticing – he wakes up and makes the subject in whom the virus has reactivated able to infect. This virus has so far been considered not very dangerous after all, but very recent studies seem to indicate with decidedly solid data that the Epstein-Barr virus infection is not a sufficient condition, but necessary, for the onset of a very serious and very disabling disease. , multiple sclerosis. It would seem a relationship similar to that between papillomavirus and cervical cancer (and more rarely other organs): not all those who become infected with papilloma develop cancer (fortunately), but those who do not become infected do not they never develop it.
If confirmed, the discovery concerning multiple sclerosis is very important. Considering, however, that this virus infects more than 50% of children by the age of 8 (and the percentage rises to more than 80% by the age of 19 and exceeds 90% in adults), and that it reactivates and makes individuals contagious asymptomatic, knowing only the potential danger in itself would not help us: it would be practically impossible to defend against infection, unless you move to the Moon.
Of course, the situation would be very different if there was an effective vaccine, but this vaccine does not exist at the moment. However – also in this case – mRNA vaccines against the Epstein-Barr virus are being tested, and if they work they could make multiple sclerosis go the way that cervical cancers have done in countries where vaccination against the papilloma virus was particularly extensive (not in Italy, unfortunately): this type of cancer stands
literally disappearing. With a vaccine, even multiple sclerosis could disappear.
The list of viruses (and bacteria) against which we do not have a vaccine could go on for hundreds of pages, but I think these examples are already enough to make you understand what revolution can be that of mRNA vaccines.
gives “The formidable undertaking. Medicine after the mRNA revolution“, By Roberto Burioni, Rizzoli, 2022, pages 208, € 17.50