02/27/2024 – 22:00
Brazil surpassed 970,000 probable cases of dengue, according to data from the Ministry of Health. The data goes up to epidemiological week 8, ending on Saturday the 24th, and was announced this Tuesday the 27th. This means that, in two months , the country has already recorded more than half (58.6%) of all notifications last year, when 1.65 million infections were observed.
Faced with this scenario, seven federative units (AC, DF, GO, MG, ES, RJ and SC) – most of them in the Center-South axis of Brazil – and 154 municipalities declared an emergency, according to the latest daily report from the department . At a national level, the incidence of dengue is 479.3 cases per 100 thousand inhabitants – most of the decrees occurred after the city or state exceeded 300 cases/100 thousand inhabitants.
For Julio Croda, infectious disease specialist at the Oswaldo Cruz Foundation (Fiocruz) and professor at the Federal University of Mato Grosso do Sul (UFMS), the accumulation of cases at this time of year is, in fact, “unexpected” and “unusual”. “We are going to experience the worst year of the dengue epidemic that we have ever seen in the country”, he warns.
“The expectation is that these numbers will continue to grow, and that we will surpass the historical record for the number of cases and, unfortunately, also the number of deaths”, he adds. Considering that our surveillance system has changed little in recent years, the doctor recalls that there are an estimated nine underreported cases for each official record of a probable case, in addition to asymptomatic cases. In other words, the real number must be much higher.
In a press conference this Tuesday, the 27th, the ministry highlighted that the increase in cases occurs at a time when not only dengue fever is circulating, which raises concerns. “We have chikungunya, we have covid, we are also now starting a season of respiratory viruses, which we need to pay attention to”, said Ethel Maciel, Secretary of Health and Environment Surveillance at the Ministry of Health.
“At the first signs of symptoms of fever, body pain, joint pain, pain behind the eyes, malaise, headache, spot on the body, seek a health service”, he asked. Minister Nísia Trindade announced a “D-day” to combat dengue, which will take place on Saturday, 2nd, with prevention and incentive actions to eliminate outbreaks of the Aedes Aegypti mosquito, dengue vector – 75% of breeding sites are within our houses.
The number of deaths due to dengue is 195 to date. Last year, there were 1,094 deaths, an all-time record. The lethality (the ratio between the number of deaths and probable dengue cases), however, is lower than last year, according to the ministry. Comparing the first eight epidemiological weeks of each year, the fatality rate was 0.07 in 2023, and now it is 0.02.
In press conferences held throughout this year, authorities have already drawn attention to this drop, attributing the result to better preparation of health teams to manage cases. Dengue has no specific treatment, but an adequate hydration protocol saves lives.
Even though there are a few days left until the end of February, the accumulated number of cases in the first two months of this year is already 236.37% higher than that recorded in the first two months of last year. According to the ministry's arbovirus panel, 289,366 probable cases of dengue were recorded in January and February 2023.
In the latest weekly report from the department, which provides slightly more detailed information, published on February 20, the highest number of cases this year occurred in epidemiological week 5, which covers the period between January 28 and February 3, when there was a record of 175,015 probable infections. The 2023 peak occurred in week 15 (111,840), between April 9 and 15.
Dengue has a seasonal behavior. According to the Ministry of Health, the increase in the number of cases and the risk of epidemics occurs mainly between the months of October of one year to May of the following year.
The ideal is that we prepare for the worst. In other words, for the peak to occur between April and May”
Julio Croda, infectious disease specialist at Fiocruz and professor at UFMS
But peaks do not usually occur in the first months of the year. “We surpassed the disease peak of 2023 two months in advance”, highlights Croda.
Ethel said, at this Tuesday's press conference, that this year's case curve is atypical. Cases began to rise earlier than previously and at a “very fast” rate. The Ministry of Health has already pointed out that Brazil may be experiencing an anticipation of seasonality.
Croda thinks it is too early to be sure that the peak has been anticipated. “The ideal is that we prepare for the worst. In other words, for the peak to occur between April and May.”
At this Tuesday's press conference, Minister Nísia and Ethel stressed that it is not possible to be categorical at this moment and that many uncertainties permeate this hypothesis. “We don’t know yet, and we are monitoring the data, whether there will be a decline,” said Ethel. According to her, other important questions, if there is a decrease, are: “will the decrease be sustained?” and “it will be as quick as the climb”. All of them unanswered, she says.
Forecast
The Ministry of Health's estimate is that, this year, Brazil will reach 4.2 million cases. It is more than double last year's records and something never seen before in the country.
One of the reasons for the less than optimistic forecast is that, after many years, the four dengue serotypes circulate in the country, although DENV-1 and DENV-2 prevail. Furthermore, there is the influence of climate change and El Niño, which cause an increase in temperature and an abnormal rate of precipitation. This is the ideal scenario for the Aedes Aegypti mosquito, the dengue vector, to transmit the virus and proliferate.
At the press conference this Tuesday, 27th, minister Nísia Trindade added another factor that may be contributing to the worsening of the crisis: medium and small cities with “large numbers of cases”. “That means more internalization, more dispersion.” The department is concerned about the conditions of health services in these municipalities.
Amid this scenario, vaccination against dengue began with the only vaccine approved to date by Anvisa and which can be widely applied to the population: Qdenga, from the Japanese pharmaceutical company Takeda. The number of doses is small (around 6.5 million for this year) and, therefore, only children aged 10 to 14 from 521 municipalities will be vaccinated in 2024. The effects of the campaign in reducing cases should not be felt in the short term.
The focus of the Ministry of Health, at the moment, is to prevent deaths from the disease, which are preventable. Since November last year, as shown by the Estadãonational authorities were already communicating with states and municipalities to warn about the erratic seasonality of the disease, which required special attention and advance preparation.
The success of case management occurs in the early identification of warning signs of the disease, which indicate a worsening of the case. The sooner they are detected and treatment begins, the better the prognosis. In critical cases, hydration needs to be intravenous (in a vein).
This year, 7,771 cases of severe dengue or dengue with warning signs were recorded. According to data from the Notifiable Diseases Information System (Sinan), tabulated by the Estadão, throughout 2023, 21,636 such cases were reported. In the first eight weeks of last year, the cumulative figure was 1,953.
We should declare an emergency, says infectious disease specialist
The number of cases has clearly surpassed the endemic channel, indicating an epidemic. Although it focuses mainly on the Center-South axis, Croda believes it is important for the Ministry of Health to declare an emergency at national level – and not just because of the very significant number of cases outside the expected season. “We have other relevant facts: a chikungunya epidemic in Minas Gerais and an oropouche (fever) epidemic in the North, of which we do not know the real impact.”
“Declaring an emergency is an appropriate action from the Ministry of Health's point of view, because it can help bring resources, guidance, information and, mainly, mobilization to municipalities, states and the population. More than just an administrative act, it is an act that involves raising awareness among managers and society.”
When asked at the press conference this Tuesday, 27th, about the possibility of declaring a health emergency of national interest, Nísia was evasive. “Everything necessary to do to reduce the impact of dengue, to save lives, at this moment, is what we will do,” she said.
“If we are going to reach a situation, due to the level of assistance, of a lack of beds, we are working to ensure that this situation does not exist”, he said. “We are working very carefully to adequately inform the population, but without saying 'look, we are going to reach an emergency”.
The minister then cites three other emergencies experienced in the country. “The Zika emergency, which had a very concrete issue, the strong risk of congenital syndrome. Absolutely a new fact, it had not been described anywhere and it was not known where it would end up. Another emergency, this one of international importance, was Covid-19, with high transmission and the collapse of the health network. Another, caused by lack of assistance, is the Yanomami crisis.”
“We have to be careful. They are very different situations. Doing the right thing at the right time,” she concluded.
Among these statements, she goes so far as to say that “there are no universal indicators for this”. It was not clear whether she was referring to the possible lack of beds or the declaration of emergency.
However, according to decree No. 7,616/2011, which provides for the declaration of a Public Health Emergency of National Importance (Espin), epidemiological situations that: present a risk of dissemination are considered to be outbreaks or epidemics – and Espin decrees national, are produced by unexpected infectious agents, represent the reintroduction of an eradicated disease, present high severity or exceed the response capacity of the Unified Health System (SUS).
The current dengue scenario, according to experts interviewed by Estadãowhile in the first possibility, that is, “there is a risk of national spread”.
Action
The Ministry of Health mediates conversations between Fiocruz and Takeda to transfer vaccine technology, which would allow the production of the vaccine to be increased. Furthermore, it invests in innovative technologies, such as the Wolbachia method.
In this method, mosquitoes or eggs are altered in the laboratory to carry Wolbachia bacteria, which blocks the transmission of arboviruses. Insects are released into the environment to compete with wild ones, replacing them. The technique has yielded surprising results around the world, with reductions of up to 90% in the incidence of dengue in some locations. Last year, the department invested R$30 million in the strategy.
The ministry also announced the increase in resources reserved to support States, municipalities and the Federal District in dealing with emergencies, which include dengue, to R$1.5 billion. Last November, the ministry had already promised R$256 million.
According to Ethel, the first ordinance that allocates these additional resources was published this Tuesday. The DF and nine municipalities in GO, MG, RJ and SP were covered.
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