The effectiveness of boosters with the COVID vaccine bivalent against severe Omicron infection, was demonstrated in a study conducted from September 1 to December 8, 2022 (Dan-Yu Lin). In particular, bivalent vaccines provided additional protection against severe Omicron infection, in people who had previously been vaccinated, although this protection tended to decrease over time. However, it should be noted that the effectiveness of the bivalent boosters was higher than that of the monovalent boosters. A sub-unit vaccine consisting of two components was designedi, the virus receptor part (RBD) and the N-terminal domain (NTD) of the viral spike protein. This new vaccine which includes NTDimproves the responsiveness of T cells and the neutralizing ability of antibodies against multiple variants of SARS-CoV-2.
This initial study (Isabelle Montgomerie) appears to provide a promising booster vaccination strategy able to protect against a greater number of variants of SARS-CoV-2. The bi-directional relationship that exists between the gut microbiota and COVID-19was the subject of a study (Tanya Ralli) which indicated that the intestinal microbiota is able to have an impact on the lungs, so as to condition the evolution of the COVID-19 infection, while SARS-CoV-2, a in turn, it can alter the intestinal microbial composition. This study allows to better understand the mechanisms through which the microbiota can influence the outcomes of the disease and at the same time to envisage the use of prebiotics, probiotics and possibly also fecal transplantation during COVID-19 to improve the prognosis. However, we are at the dawn of a new therapeutic approach which could prove to be extremely useful even if, in order to be implemented, it necessarily requires further studies to be carried out.
A research has shown (Tetsuya Suzuki) that, despite the detection of viral RNA in the nose and pharynx of infected subjects subjected to oxygen delivery via nasal cannula, there is no dispersion of the virus in the environment, since neither the viral RNA nor the viable virus were detected in an air sample obtained half a meter away from the nasal cannula itself. The current slight increase in infections that has been reported in Italy in the last weekwhich is also associated with a slight increase in hospitalizations, even in the presence of a clear reduction in deaths (-18%), should not surprise too much, since it testifies to a fluid epidemiological condition with periodic expansions and contractions of the spread of SARS-CoV-2 typical of an endemic phase of the disease. Moreover, the high number of vaccinated people, the presence of a rather widespread natural immunity both of the infection alone and of the infection that occurred in vaccinated people (hybrid immunity), leads us to believe that the current epidemiological situation is not particularly alarming. As it pertains the protection conferred by SARS-CoV-2 infection against reinfectiona systematic review and meta-analysis covering 65 different studies carried out in 19 different countries conducted from the start of the pandemic to the end of September 2022 (COVID-19 Forecasting Team), indicated that the protection conferred by a previous infection with pre-Omicron was very high and remained so even after 40 weeks. However, the protection against the Omicron 1 variant was lower and tended to decrease faster than previous variants. Against this result, however, it was significant that protection against severe disease was high against all variants, including Omicron variants. This study therefore emphasizes the importance of immunity conferred by a previous infection which, together with vaccine administration, needs to be carefully evaluated in the future to establish COVID-19 disease control strategies. The efficacy and safety of a vaccine against the protein subunit of SARS-CoV-2 (ZF2001) in children and adolescents aged between 3 and 17 years, has been the subject of two studies, one in phase 1 and one in phase 2 (Lidong Gao) which indicated that the vaccine administered in this age group is well tolerated and stimulates an adequate immune response, even if the neutralizing capacity of the vaccinated serum is lower compared to Omicron 2. A study conducted in Switzerland (Lea Portmann), based on data obtained from the national COVID-19 and influenza registers, considered hospitalized patients, aged 18 years or older, with Omicron variant infection and hospitalized between January 15 and March 20, 2022. The results of this research showed that there is a significant increase in the risk of hospital mortality in COVID-19 patientscompared to those with flu, even if the percentage of hospitalization in intensive care appears to be quite similar for both diseases.
A cohort study (Alan C. Kwan) confirmed this the increased risk of developing diabetes after SARS-CoV-2 infection even in this epidemiological phase in which the Omicron variant has become dominant. This risk is higher in unvaccinated than in vaccinated patients, which suggests a protective effect against the development of diabetes by vaccination. Even if the mechanisms leading to the development of diabetes in the course of COVID-19 have not yet been fully clarified, it is more than likely to believe that the persistent inflammation induced by SARS-CoV-2 could contribute to the emergence of resistance against the insulin. However, it is not possible to extrapolate from this study whether the risk of cardiometabolic sequelae of COVID-19 can also be mitigated by vaccination.
A study was conducted in China (Zhenyu Zhong) which proved that early vaccination with a non-mRNA vaccine in people with a previous, non-active inflammation of the eye (uveitis), causes worsening of self-reported symptomatic uveitiscompared to deferring vaccination, even if three months after vaccination there were no differences in disease prognosis and vision.