Nasal or oral sprays: will these be the next anti-Covid vaccines? The world of science looks with some expectation at the so-called mucosal vaccines, but “we are still in a rather interlocutory situation. As the European Medicines Agency, Ema, what do we expect? It is very uncertain: we hope to be able to see clinical or use results real with CanSino’s Chinese vaccine, say mid-2023. at this point”. This is the picture traced to Adnkronos Salute by Marco Cavaleri, head of the strategy for health threats and vaccines of the EMA.
“Clearly there is great interest both on the part of those involved in public health and research, and on the part of a regulatory agency such as the EMA in seeing these vaccines advance and understanding what their value may be in the future – highlights the expert – We are monitoring the situation and talking to those who are developing these products. At the end of last year I also participated in a meeting organized by the Nih”, the US National Institutes of Health, “to try to understand how we can advance mucosal vaccines and I would say that we are still in a fairly uncertain situation, since we are waiting for the results of clinical trials to actually understand if these vaccines can be a possibility and if we can eventually approve them”.
At the moment, explains Cavaleri, “we are looking carefully at the CanSino vaccine, which is in use in China. It is an inhaled vaccine that uses an adenovirus. However, it would be very interesting to be able to have data on its efficacy and level of protection that it manages to produce. We are then looking at other types of mucosal technologies, including vaccines that use a live but attenuated virus. There is a vaccine that is in clinical trials and for this reason too we are trying to understand how effective it is” . To date, “that’s all that can be said,” he points out. “The idea – she adds – is that these vaccines may be more effective in also preventing infection and transmission of the virus. It is what is expected”.
As for the projects underway, the EMA expert reports that “there are several companies at work”, including in the US, for example “Vaxart”, to name one, which is studying an oral vaccine. “There are several small companies that work on this type of project and perhaps find it more difficult to carry out the clinical development of products”, observes Cavaleri. Another example of a company that is focusing on similar products is Codagenix, which is developing the intranasal attenuated virus vaccine.
“So there are also vaccines developed in the US that are specifically mucosal, not just the Chinese vaccine and another Indian vaccine, also approved. But these two are already in the real world and it would be extremely interesting to have data on what their effectiveness, especially at the moment from China, if it is used, given that there is no shortage of cases”, he reflects. The EMA is “in contact with CanSino”, reports Cavaleri. “As always with companies that don’t come from the western world, it’s more difficult to advance quickly, but our door is always open. Then let’s see what we can do.”
The recall perspective
A barrier already at the entry gates of the Sars-CoV-2 virus, nose and mouth, therefore more able to avoid contagion. This is therefore the promise of anti-Covid spray vaccines, or rather mucosal vaccines. “The expectation is that they can also be more effective in preventing infection and transmission of the virus. Even if what we unfortunately have to accept is that these vaccines too may need continuous boosters”, suggests Cavaleri, “because – he clarifies – mucosal immunity, as far as we know, is also not maintained long-term with respiratory viruses.”
Beyond the need for recalls, however, the expert reiterates, “undoubtedly the mucosal vaccine could be an alternative or something that can help achieve a level of protection from infection and transmission” of Covid, “which unfortunately current vaccines fail to achieve. Although, it should be noted, it is not that they are completely ineffective from this point of view. They are simply not very effective, “concludes Cavaleri.
