Covid vaccine, effective even 3 months after the second dose: the study

“Three months after the second dose, the anti-Covid vaccine confirms its effectiveness despite the foreseeable reduction in the antibody titre”. This is the figure announced by the Niguarda hospital in Milan, based on the results of the ‘Renaissance’ clinical study which examined “a vast series of cases, the largest to date in Italy – underline the Asst Grande Ospedale Metropolitano – made up of 2,415 health workers on duty in Niguarda, who completed the cycle with Pfizer / BioNTech’s Comirnaty * vaccine between January and February “. From the research, conducted in collaboration with the State University of the Lombard capital, “encouraging results” emerge, reads a note. The objective of the study was to “evaluate the immune response” induced by the Covid-19 vaccine, “photographing it at different time intervals. First of all, the response was evaluated 14 days after the second dose (the results were released last March), and now the research is strengthened with data 3 months after the completion of the immunization cycle “. “With the first analysis we had observed an antibody response in over 98% of the vaccinated – says Francesco Scaglione, director of the Laboratory of Chemical Analysis and Microbiology of Niguarda – After 3 months from the second dose, in all those who had responded positively to the vaccine it persists. the antibody titer in the serum. As expected, the mean values ​​detected naturally decreased over time, by about 50% on average, but in any case they are still much higher than the negativity threshold. There is still no confirmed data about the cut-off, i.e. minimum antibody titer to be protected. We will certainly know more when the study completes its process, which also requires a dosage at 6 and 12 months later. In the meantime – Scaglione remarks – the validity of the vaccine is also confirmed by the fact that no one has developed a symptomatic disease during the months of the third pandemic wave “. Another data highlighted by Niguarda concerns the internal health surveillance erna of the hospital. “Since the vaccination cycle on over 4,500 employees has been completed – report from Asst – none of these have developed symptomatic Covid-19”. Following the tests conducted, “14 people were positive, all asymptomatic or paucisymptomatic”. For Scaglione “this data is also particularly positive. Considering the circulation of variants” of Sars-CoV-2, the head of the laboratory specifies, “the study suggests that the vaccine in some way can confer protection even in these cases”. However, the experts of the Milan hospital highlight that the antibody response observed in the research (IgG antibodies directed against the Rbd receptor of the coronavirus Spike protein) reflects only part of the complex protective mechanism activated by the body with the vaccine. In addition to antibodies, there is the response mediated by ‘immune soldiers’ such as memory cells and natural killers, essential for prolonged protection over time. “Once the first phase of the study is concluded – points out Scaglione – we will deepen the response of T cells, those responsible for memory, to understand if the vaccine can induce a very long-lasting immunity”. Other data also arrive from Niguarda. “With a retrospective analysis – reports the local social health company – the impact of vaccination on workers was assessed, to establish whether the extent of the side effects was such as to negatively affect the hospital’s ongoing activities. from an even wider case study than that of the Renassaince study, with a sample enlarged to 4,043 people, the research reveals that only 1.6% of Niguarda’s professionals had to take time off from work due to side effects, however mild, after the first administration of the Comirnaty vaccine, and about 6% after the booster which, as known, evokes a stronger response than the first injection. On average the absences were 2 days, with more pronounced side effects in workers who had previously contracted the virus “. This type of survey, asst commented, “demonstrates how a broad vaccination campaign within a company does not critically interfere with work activities, confirming once again the importance of broader immunization. possible, which reduces the risk of getting sick with Covid “.