A type of pneumonia known as “silent” has generated concern among doctors and parents. Although less noticeable in the early symptoms, this form of the disease – also called asymptomatic, atypical or subclinical pneumonia – can lead to serious complications if not diagnosed and treated correctly.
Unlike “typical” pneumonia, caused by the bacteria Streptococcus pneumoniaewhich causes classic symptoms such as high fever, intense cough and chest pain, the silent version usually develops more discreetly. In general, signs appear only in the most advanced stages of infection, increasing the risk of hospitalization, especially among children.
Hence the importance of parents and guardians are aware of some signs associated with pulmonary infections. They deserve attention difficulty eating, lack of willingness to perform daily activities, chest squeak, withdrawn rib, little desire to pee and episodes of low fever.
Microorganisms like Mycoplasma sp., Chlamydophila sp. and some respiratory viruses-including those of influenza and coronaviruses-COV-2, causer of COVID-19-are among the leading causes of this type of pneumonia. “Since the pathology is the same, we cannot say that silent pneumonia is a different disease from typical pneumonia,” explains pulmonologist Marcela Costa Ximenes of the Brazilian Society of Pulmonology and Tisiology (SBPT). “This is not even a new variant,” he adds.
Although it is not a mandatory notification disease in Brazil and the scarcity of examinations that accurately identify the causative agent of infection, pneumonia still represents a significant challenge for the health system, especially with regard to atypical staff. The lack of specific data on these cases limits the understanding of the real dimension of the problem.
In 2024, there was a 5% increase in the total number of hospitalizations for pneumonia in the Brazilian public health system compared to the previous year – 701 thousand patients were admitted, compared to 666.9 thousand in 2023, according to Datasus. Even more worrying is the 12% growth in the number of disease deaths: 73,813 deaths in 2024 compared to 65,846 the previous year.
The State of São Paulo recorded growth above the national average in both hospitalizations and deaths. Municipalities of São Paulo also reported an increase in cases of pneumonia without fever, which raises alert to atypical forms of infection that can make it difficult to diagnose early diagnosis.
These numbers reinforce the need for more detailed epidemiological surveillance and more attention to the less common manifestations of the disease. At the request of the Einstein Agency, the São Paulo State Department of Health raised that, without distinction of typical and atypical pneumonia, hospitalizations increased by 6.7%. The deaths jumped almost 13% between 2023 and 2024: from 23,084 to 25,983.
“Through notifications from laboratories that conduct analysis of the few samples of viruses and bacteria collected during diagnostic exams, it is possible to estimate that atypical pneumonia represents 30% to 40% of the total pneumonia tables,” says Ximenes. “This is equivalent to one to four asymptomatic cases for every 1,000 people.”
Reasons behind the current outbreak
For pneumopediatrician Luiz Vicente Ribeiro, from Hospital Israelita Albert Einstein, the current outbreak of silent pneumonia derives, above all, from the circulation of two bacteria: Mycoplasma sp. and Chlamydophila sp. Before the Covid-19 pandemic, it was believed that they had a seasonality of two to three years, but that seems to have changed.
“Pneumonia in children have always been very common. But as these young people were removed from schools to protect them from coronaviruses, this led to a dramatic reduction in the frequency of respiratory infections as a whole,” says Ribeiro. The decrease in the circulation of these microorganisms prevented children from developing immunity against them.
With the resumption of normal life, the population became more susceptible to such infections. “Back in schools, many children had to deal with environments crowded with viruses and bacteria with which they had not created resistance after years at home,” explains the doctor.
For him, the tendency is for this phenomenon to continue until the population has immunity against these infectious agents. Until then, it is possible that outbreaks of atypical diseases, such as silent pneumonia itself, happen more frequently and last longer – every month of autumn and winter, for example.
Diagnosis and Treatment
The diagnosis of silent pneumonia is similar to that of typical pneumonia. Normally, a clinical evaluation with anamnesis, noise auscultation examination and chest radiography is performed. In some cases, an analysis of material collected on respiratory pathways is indicated by the means of exams such as C-reactive protein (PCR). This investigation is able to identify a good amount of viruses and respiratory bacteria, but as its result does not alter the treatment approach, it is often set aside.
From the diagnosis, treatment is based on the patient’s clinical history, with an approach that can propose the use of different medications. In care with typical pneumonia, the general recommendation is to use common antibiotics such as penicillin. However, this class of medicines is not effective in combating Mycoplasma sp.which is behind many atypical (or silent) cases.
The delay in seeking medical care can significantly increase the risk of serious health complications. Problems include kidney, pulmonary or cardiac, stroke (stroke), need for mechanical ventilation, sepsis, dialysis and even encephalitis.
Prevention Methods
Since silent pneumonia is also transmitted through direct contact with contaminated secretions, preventive guidelines are similar to the recommended care during Covid-19 pandemic: use of mask in very crowded environments (especially in hospitals and medical clinics), use of gel alcohol, cleaning hands well with soap and soapy, and avoiding contact with flu symptoms.
Although the pneumococcal vaccine protects only against typical pneumonia (Streptococcus pneumoniae), it remains highly recommended for vulnerable groups such as children, the elderly and people with chronic diseases. Immunization is available free of charge by the Unified Health System (SUS) during annual campaigns.
If you are suspicious of some symptom in you or your child, look for an emergency service. “Despite the change in the seasonality of infections and the possible risks that pneumonia without symptoms can bring, it is important to remember that we already know this disease,” says Ximenes. “There is no reason to create fuss.”
This content was originally published in Understand what silent pneumonia is, which has warned health authorities on the CNN Brazil website.
Source: CNN Brasil
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