FewCruz warns of low risk of poliomyelitis recurrence in Brazil due to low vaccination among children

Photo: Reproduction / Fiocruz

“We have a red light in Brazil because of low vaccine coverage, and it is important to do something about it. We cannot wait for the tragedy of virus relapse to take action,” the scientists said.

“There is a serious possibility that polio will re-emerge in Brazil, as was the case with measles, in 2018. Therefore, we need to focus on the risks and the need for vaccination.” The warning came from Fernando Verani, an epidemiologist at the National School of Public Health (ENSP / Fiocruz).

More than 500,000 children in Brazil have not been vaccinated against the disease. The high number of PAHOs (Pan American Health Organization) ranked the country among the countries with the highest rates of infection. According to the agency, if the immunization coverage in countries does not exceed 95%, the risk of litigation increases.

Akira Homa, director of Biomanguinhos at Fiocruz, says only 67% of Brazilian children have been vaccinated, 28% less than the norm. According to Homer, the low adherence to the vaccine is worrying, mainly due to Brazil’s proximity to countries such as Haiti and Bolivia – where there is a high risk of infection.

“The more a virus is transmitted, the more mutations it goes through and it could become a new threat, as if it were a wild virus. If the vaccine coverage of the population is 95%, there will be no problem. But the coverage is so low, it turns out to be a risk, “said the researcher in an interview with Estadão.

Poliomyelitis has been officially eradicated in Brazil and the Americas since 1994. Fiocruz’s director was one of the leaders in the country’s campaign to eradicate the disease in the 1980’s. At the time, Homa recalled the introduction of the oral vaccine. And the national vaccination campaign was instrumental in eradicating polio. According to the researchers, another key factor in the success of vaccination was the high level of social adherence. However, with low vaccine coverage, Brazil is at risk of recurrence of the disease.

Despite the severity of the polio outbreak, Brazil has not met its goal of vaccinating 95% of children since 2015. According to the National Immunization Program Information System (SI-PNI), immunization coverage is very low, including three initial doses of the vaccine: 67% in 2021.

And when it comes to booster doses, drops, protection is even lower: only 52% of children were vaccinated. In the Northeast and North, the situation is even worse, at 42% and 44%, respectively, for a full vaccination schedule with five doses.

“As long as polio exists anywhere on the planet, there is a risk of the disease being imported. It is a dangerous and highly contagious virus, for example, more contagious than Sars-CoV-2. We have a red light in Brazil because of low vaccine coverage and something needs to be done. We cannot wait for the tragedy of relapse of the virus to take action, “Verani said in a statement.

In February of this year, authorities in Malawi, Africa, declared an outbreak of the disease after a 3-year-old child became infected with the wild type 1 polyvirus. The strain is genetically linked to the virus spreading to Pakistan, one of two countries. In the world, with Afghanistan, where polio remains endemic.

The girl developed the most severe form of the disease, acute flaccid paralysis, the effects of which are often irreversible. The latest case of polio in the African country was reported in 1992 and the whole of Africa was declared free of the disease in 2020.

The complete vaccine avoids the risk of mutation in the infected polio virus. In Brazil, the vaccine known as “Gotinha” is used in public networks to strengthen against the disease. It is worth mentioning that the vaccine does not pose any risk to the baby as he has previously received inactivated immunizations. But there is a risk of infection for those who are not vaccinated.

Edson Elias, chief virologist at the Oswaldo Cruise Institute (IOC) Enterovirus Laboratory, explains, “When the population has low vaccination coverage, there is a risk of the virus mutating because it is transmitted from person to person, becoming an attacking strain.” In the statement.

Poliomyelitis is an acute infectious disease caused by the wild poliovirus responsible for various epidemics in Brazil and around the world. It can cause everything from common cold-cough-like symptoms to serious nervous system problems, such as irreversible paralysis. Children under the age of five are most affected.

Poor surveillance

According to Verani, another cause for concern for disease recurrence is the low efficiency of disease surveillance techniques to contain potential outbreaks. Researchers explain that almost three years ago (since Zaire Bolsonaro took over the presidency of the Republic), epidemiological surveillance protocols in Brazil were weakened.

“They are intended to detect and prevent infectious diseases. Sewerage samples from the cities were not collected as often as expected, and there was no continuous reporting or investigation into possible cases of acute flaccid paralysis. The country has the resources and skills to eradicate polio, but it is not taking the necessary steps, ”the scientist warned.

He said that in Malawi, the case of the infected girl was quickly identified and the local people were re-vaccinated against polio, which prevented a viral epidemic. Experts fear that if the disease is imported, the health system will not be able to act quickly to curb its spread.

“If the virus is reintroduced and cases are not reported quickly, we could have an epidemic,” he said. Children are vulnerable today due to our low immunization coverage. This could lead to hundreds or thousands of paralyzed children, “warned ENSP / Fiocruz researchers.

Dylan Raimundo do Nascimento, a researcher at Casa de Oswaldo Cruz (COC / Fiocruz), says the coronavirus epidemic has shown that the world currently has no borders. It’s much easier and faster in humans, so the chances of transmitting the virus increase. “

“There is a serious possibility that polio will re-emerge in Brazil, as was the case with measles, in 2018. Therefore, we need to draw attention to the risks and the need for vaccination,” the expert warned.

In order to implement measures to reverse the downward trend in the immunization coverage of the National Immunization Calendar for Children, Adolescents, Adults and Adults, Pregnant Women and Indigenous Peoples, Has signed a protocol aimed at implementing a program to restore coverage.

Recent studies indicate that in some states of Brazil, the use of some immunizations in the child population will decrease by 65% ​​by 2020. Worldwide, the decline was about 30% in the first months of that year. Of the 15 vaccines that should be given up to the fourth year of life and about which more information is publicly available, at least nine are lower than the rates recommended by health authorities.

They are vaccines that protect against about 17 serious infectious diseases. Some of them are highly contagious, such as measles and whooping cough, or incurable, such as meningitis and poliomyelitis virus infections.

“[…] The effects of some (conditions) seem to have intensified in recent years, with the intensification of anti-vaccination groups and fake news spreaders on social networks and the Brazilian government publicly speaking out against vaccinators, “said pediatrician and epidemiologist at the Federal University of Pelotis (Federal University of Pelotel). Fernando Barros, a professor at the University of Pilotus (UCPel) who follows the evolution of childhood immunization in the country, explains the inadequate adherence to childhood immunization campaigns in the country.

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