Monkeypox, those who do not get vaccinated risk 14 times more
Those who are not vaccinated against monkeypox, even with a single dose, are 14 times more likely to become infected than those who received the vaccine at least two weeks before exposure. This is the result of a US study conducted by the CDC (Centers for Disease Control and Prevention) and published in Jama. The CDC currently recommends two doses of the Jynneos vaccine 4 weeks apart for people at high risk of infection due to confirmed or suspected exposure to an infected person.
Under examination 5 thousand people affected by smallpox
The research, which responded to the objective of evaluating the effects of monkeypox vaccination efforts, focused on analyzing the vaccination status of 5,402 infected between July 31 and September 3, 2022. It should be noted that, at the September 28, there were too few who, at risk of contagion, had completed the series to evaluate the effects of 2 doses.
In particular, about 85% of the cases of infection occurred among unvaccinated people, while 1.4% involved those who had received at least one dose 14 days before the disease. Finally, 5% occurred among those who received at least one dose 13 or fewer days before illness, while 8% involved people with vaccine status.
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"The duration of immunity after a single dose is not yet known," the study authors stressed. "And because vaccine efficacy and duration of protection are expected to be better after 2 doses, it is still important that all vaccinated people receive the second".
"Monkeypox cases are still an emergency"
Even if cases are no longer growing at the rate of recent months, the monkeypox epidemic continues to meet the criteria for being considered an international health emergency. This was established and approved by the WHO Emergency Committee.
Today we are at 915 cases in Italy (in Europe there are about 20 thousand) and the highest incidence is recorded in Lombardy, Lazio, Emilia Romagna and Veneto. The median age of those infected is 37 years and at the moment almost all are male. According to the latest WHO update, 77,934 people have been affected by Monkeypox worldwide since the beginning of the epidemic, while 36 have died.
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Less infections in high-income countries
"Overall, the conditions that justified the determination of the Public health emergency of international concern persist, as the monkeypox outbreak continues to constitute an extraordinary event posing a risk to public health due to international spread," the World Health Organization wrote.
The trend of the epidemic, however, presents marked differences between high-income and low-income countries. In the former, WHO explains, a sharp drop in infections has been observed, but to date, it is not clear whether it was "the adoption of safer sexual behavior among high-risk populations; the seasonal reduction of large gatherings; the increase in pre- and post-exposure vaccination rates; the possible increase in immunity following infection among those most at risk of contagion".
Wider diffusion in the poorest countries
On the contrary, in low-income countries, in addition to the reduced possibility of access to diagnostic tools, drugs and vaccines, the strong lack of data is worrying: in some areas of Africa, for example, it is difficult to determine whether the infections are of animal origin or whether it is human-to-human transmission. Also for these reasons, WHO has currently preferred to adopt a cautious attitude, motivated by "concern about the potential negative consequences that would result from the withdrawal of the emergency declaration at this time".
That's why the virus spreads quickly
But why does monkeypox spread so quickly? An answer comes from a second study, this time published in the Journal of Autoimmunity, conducted by scientists at the University of Missouri. The team, led by Kamlendra Singh And Shrikesh Sachdevhas identified the specific mutations in the virus that contribute to its continued infectivity.
It turns out they would facilitate monkeypox's ability to spread quickly and resist drugs and vaccines. In this regard, the research group analyzed the DNA sequences of over 200 strains of the virus in question, which has infected tens of thousands of people worldwide since 1965.
"Through a temporal analysis we were able to reconstruct the evolution of the accumulated mutations - says Sachdev -. We discovered that the pathogen is becoming increasingly intelligent, able to evade the body's immune response and spread faster in the population".
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The computer model of proteins
Experts developed a computer model of the proteins of the virus to identify the location of specific mutations and their role in the course of the disease. Five specific proteins were examined during the analysis of monkeypox strains. Results which, the experts underline, "could favor the development of more effective drugs against the disease".
"The mutation factors are certainly contributing to the increase in the infectivity of the virus - observes Singh -. This work represents the first step towards solving a global health problem".
But there is one last obstacle, that of the drugs approved by the CDC which, according to experts, have not shown optimal efficacy probably because they were originally developed to treat HIV and herpes".
"There are various hypotheses as to why these mutations can favor the replication of the virus - concludes Singh -. In the next steps we will try to identify an effective approach strategy to prevent and fight the infection".
