Country has 500,000 children without a polio vaccine, says Fiocruz scientist

This does not mean that half of the children are totally vulnerable. Even with the two incomplete regimes, minors have some degree of protection – (Photo: Reproduction)

The article previously sent incorrectly reported Akira Homma’s position at Fiocruz as director. He is senior scientific advisor. Below is the corrected version:

At least 500,000 children in the country have not been vaccinated against polio. The high number of people without protection against the disease led the Pan American Health Organization (PAHO) to include Brazil in the list of eight Latin American countries at high risk of returning the infection. In the most severe cases, the disease can cause paralysis.

According to Opas, an arm of the World Health Organization (WHO) in Latin America, low vaccination rates in these countries are a danger to the entire continent. The region has not recorded a single case of the disease since 1994. Brazil, which once had 95% coverage of the polio vaccine, currently has one of the lowest rates in its history, at 67%, according to researcher Akira Homma, senior scientific advisor Biomanguinhos, from Fiocruz. He was one of those responsible for the eradication of the disease in the country in the 1980s.

“We currently have 500,000 children in the country who have not been vaccinated,” said Homma, in an interview with Estadão. “This number is highly worrying, especially because we are close to two countries with very high risk of infection, Haiti and Bolivia.”

In Brazil, according to the National Immunization Program (PNI), children should take the injectable (inactivated virus) vaccine at two, four and six months of age. Afterwards, they take two doses of the oral immunizer (live attenuated virus), the first at 15 months of age and another at four years of age. According to official statistics, 67% of children had all three doses of the injectable vaccine. Oral vaccine coverage is even lower: 53%.

This does not mean that half of the children are totally vulnerable. Even with the two regimes incomplete, minors have some degree of protection. From the point of view of public health, however, as explained by Homma, the ideal is for all children to have both complete regimens precisely to prevent the circulation of the virus and possible mutations.

The injectable polio vaccine has been available in Brazil since 1973. But it was only in the 1980s, with the introduction of the oral vaccine and national vaccination campaigns (Zé Gotinha was created in these actions), that the disease was finally eradicated, in 1989. “We had the mobilization of the whole society”, recalls Homma. “We managed to vaccinate 18 million children in a single day.”

In a note, the Ministry of Health reported that “it closely monitors vaccination coverage and has worked to intensify the strategies necessary to reverse the scenario of low coverage”. The folder also reported that it recommends states, municipalities and the Federal District to carry out the active search for immunization and reinforces the importance of maintaining routine vaccination actions. The ministry also said that the dissemination of information on the safety and effectiveness of vaccines as a public health measure is also part of actions carried out throughout the year.

Has polio vaccination coverage never been so low?

Unfortunately, coverage not only of polio, but of all vaccines has been gradually falling for five or six years, and more sharply, in the years of the pandemic, even due to the recommendations of social isolation. But the truth is that coverage was already falling, not only in Brazil, but all over the world. In 2019, the World Health Organization (WHO) named low vaccine coverage as one of the top ten public health problems in the world. The situation is really serious and worrying a lot because what we call the population of susceptible people, of unprotected people, has been growing. Four weeks ago, we had a case of polio in Malawi, which is considered a polio-free country. More recently we had another case of polio in Israel, which is traditionally a country with high vaccination coverage. Both times they were imported cases.

Is there a real risk of polio returning to Brazil?

Yes, the importation of polio exists and, in Brazil, because of these low vaccine coverage, we are already considered a high risk country for reinfection, according to the classification of the Pan American Health Organization (PAHO). As well as Brazil, Ecuador, Venezuela, Guatemala, Dominican Republic and Suriname are in this classification, in addition to two other countries where the risk is considered very high: Haiti and Bolivia. Note that we are surrounded by countries at risk of reinfection, and polio was considered eliminated throughout Latin America in 1994.

Is polio still endemic in any country?

In Pakistan and Afghanistan. But the bigger problem is that there are other countries in the Middle East and Africa where, because of low coverage, cases of polio with live attenuated vaccine-derived viruses are emerging.

Could you explain how exactly this mechanism works?

The Sabin vaccine (oral polio immunizer) is made from live attenuated viruses. Children who receive the vaccine shed the virus into the environment. With very low vaccination coverage, this virus can begin to circulate among unimmunized people. The more a virus circulates, the more mutations it undergoes, and it can become a new threat, as if it were a wild virus. If the vaccination coverage of the population was 95%, there would be no problem. But with coverage so low, it becomes a risk. In the case of Brazil, the coverage of the injectable vaccine is 67%; that is, we have more than 30% of children who have not had the vaccine. There are practically 500 thousand unprotected children. That is why PAHO included Brazil among the countries at high risk for the return of polio. The number is even more worrying because we are close to two countries with very high risk of infection, Haiti and Bolivia.

What are the reasons for such low coverage, in your analysis?

There are several reasons, there are many published works. One of the main reasons is that we are victims of our own success. As we don’t have more outbreaks of the disease, the population doesn’t see more cases, doesn’t see sick people, and people think they don’t need to be vaccinated anymore. It wouldn’t be necessary if the disease were completely eradicated worldwide, but as long as there are countries with polio, we have to continue vaccinating children precisely to prevent the wild virus from entering the country, especially with the high number of susceptible people. But I also think that there is a need to better inform the population about the polio situation, to call people to get vaccinated, this transparent information no longer exists. There are also other problems that the population points out, such as the opening hours of health centers that coincide with work hours.

And what is the solution?

We are proposing a project to regain high vaccine coverage by working at the edge, in the municipalities, where the protagonists of vaccination are. We are following the daily routine in 41 municipalities in two states, Amapá and Paraíba, and based on these observations we will prepare a specific action plan for each city. The idea is to expand to the rest of the country.


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