Healthcare workers and the elderly who, six to seven months after the first two doses of the vaccine, become infected again. This does not mean that the vaccine is not effective, it simply means that the effects diminish over time. And that therefore serves the third dose. The confirmation comes from the cases of doctors and nurses who have returned positive to the virus, even in structures that house the elderly and disabled. The last case in chronological order is that of the San Germano di Varzi health residence, on the border between Lombardy and Emilia. An operator, despite having been vaccinated last spring, infected fourteen disabled guests between the ages of 18 and 50, also all vaccinated. To date, the employee Asa is at home in quarantine and the guests, all asymptomatic, are isolated inside the structure. Ats has started the epidemiological investigation and is monitoring the situation.
Positive without symptoms
The operator Asa (who provides assistance to the disabled) in the Residenza San Germano (which assists 40 people and joins the retirement home which has 107 elderly people) had no symptoms. She discovered that she was positive for the virus following a check like many others, which the RSD regularly promotes. “We screen both staff and guests daily – explains Nicoletta Marenzi, director of the facility -. Also in this case, the employee was subjected to a rapid swab, material that Ats also provides us for the patients and, to her surprise , was infected with Covid. The operator had been vaccinated last March, so the virus affected her slightly. The vaccine proved to be important, if not essential, to avoid a much worse situation. “
As soon as the result of the test on the Asa operator arrived, the structure took steps to subject all disabled guests to a swab (which through a special processor can immediately communicate the result). And 14 were infected. These are people aged between 18 and 50, but mostly children: all vaccinated and asymptomatic. The rapid swab was followed by the molecular swab, which confirmed the diagnosis. The situation was immediately communicated to Ats, which started the epidemiological investigation. The employee was sent home, where she is still in quarantine (in 10 days she will have to repeat the swab), while the infected people were isolated in a wing of the structure, also in quarantine.
“The situation is under control: today we do daily swabs for both the staff and the people to whom we guarantee assistance – assures Marenzi -. Guests run no risk. Fortunately, thanks to the vaccine, to which everyone has been subjected, we can feel protected from a possible worsening of the conditions. If we will subject our patients and doctors to the third dose? Certainly, but not before having assessed their antibody titer “.
Very safe vaccines against Covid
One thing is certain: vaccines are safe and effective against Covid. This is confirmed by the leaders of the same structure affected by the outbreak, supported by expert studies. Like the one led by the team of Professor Fausto Baldanti, head of the Molecular Virology Laboratory at the San Matteo Polyclinic in Pavia. Who ascertained that “1.4% became infected again after the anti-Covid injection and only 1 in about 2,000 became contagious again, therefore with the risk of transmitting the virus to others”. The study investigated the dynamics of the infection after vaccination of the 4,000 employees of the polyclinic. The aim was to verify the degree of coverage. Which, it was found, reaches 98.6% after the second dose.
The investigation in the second wave
The research was conducted during the second wave of Covid. “We asked ourselves: how much does a vaccine protect against infection? And we tried to give an answer – explains Baldanti -. The premise is that, from 1 September 2020 to 1 January last, on the almost 4,000 health workers of the San Matteo infected 7% of seronegatives and 2% of those who had HIV positive at Covid. So, before the vaccine, the last protection was represented by having had the infection, even asymptomatic, during the first wave “.
4,000 health workers vaccinated
Then the nearly 4,000 doctors, nurses, technicians, administrators and messengers of the polyclinic were vaccinated. “The result is that from January to May we had an infection rate of around 1% among people who did not have antibodies, and 0.4% among those who had them – explains Baldanti -. So the impact of vaccination substantially eliminated the possibility of becoming infected in large numbers. There have been some cases of reinfection: the cumulative 0.9%, of which 1.2% represented by health workers who had never met Covid, and they were vaccinated with two doses. Those who, on the other hand, had fallen ill, had antibodies and were vaccinated, always with two doses, is reduced to a percentage of 0.42%. In practice, a total of 33 people out of about 4 thousand became infected after the vaccine . Two of them had had Covid and received the serum, while 31 had not previously fallen ill, but had only had the vaccine. This tells us that more stimulations confer greater immunity. “
The investigation of post-infection symptoms
The study goes on to investigate post-infection symptoms. Of the 33 operators of San Matteo who became infected, despite being vaccinated, 17 were asymptomatic, so they were intercepted during periodic checks, while 16 suffered from mild symptoms.
At this point the question is: how many of the infected operators, even after vaccination, were also found to be contagious? “The isolation of the virus in culture was present in these 33 people in half of the cases, and only 2 of them transmitted the infection to their families – reveals the virologist of San Matteo -. If we compare the 2 people in question to the total of almost 4,000 vaccinated, we deduce that the possibility of transmitting the infection is about one case every 2,000 “.
The result, according to Baldanti, is more than comforting, especially considering the fact that “these data were collected during the second pandemic wave, when the virus was still circulating.” So – comments the virologist – the more you vaccinate, even with a third dose where ‘is necessary, and less will circulate. We cannot expect it to be a sterilizing infection, it is infrequent. In addition to this, the possibility that the infected person can transmit in turn exists, even if it is a rare thing “.