100 Faces of Pneumococcus. How to Avoid Them? Prof. Aneta Nitsch-Osuch: 90% of Patients Are Adults

During the fall and winter season, the most talked-about issues are flu, COVID-19, and the respiratory syncytial virus (RSV). This is justified – these viruses are dangerous, cause numerous complications, and can lead to death, especially in at-risk groups. But amid all the viral hype, we mustn't forget about a threat that is neither new nor seasonal – pneumococci, or Streptococcus pneumoniae bacteria, which continue to take their toll, especially among adults, says Prof. Aneta Nitsch-Osuch, MD, PhD, from the Medical University of Warsaw.

Each year , nearly 100 million cases of respiratory infections caused by pneumococci occur worldwide, nearly half a million of which result in death . These dramatic statistics stem from several factors. First, this bacterium is ubiquitous and present in our environment. Second, so-called bacterial superinfections following viral infections are very common.

An example? Influenza. The influenza virus damages the lining of the respiratory tract, paving the way for bacteria to enter. Of all the pathogens responsible for bacterial complications of influenza, the most common is pneumococcus – the king of bacterial "lurkers" for a weakened body.

It's worth remembering that not all pneumococci are created equal. Currently, over 100 serotypes of this bacterium are known, differing in virulence and antibiotic resistance. This diversity means that effective control of pneumococci requires thoughtful preventative measures – ideally in the form of vaccinations, selected appropriately for the epidemiological situation and the patient's age.

The spectrum of diseases caused by pneumococci is wide. Of course, we fear most the invasive forms, such as:

• meningitis,

• sepsis (septicemia),

• pneumonia with bacteremia (presence of bacteria in the blood).

However, in everyday practice, doctors most often encounter non-invasive infections , such as:

• otitis media,

• sinusitis,

• community-acquired pneumonia.

It is the latter – pneumococcal pneumonia – that dominates disease statistics and is the most common cause of hospitalization among adults with respiratory symptoms.

Simply put, pneumococcal pneumonia not only damages the lungs but can also shorten life . And all this in a world where we have an effective preventative method: vaccination.

Contrary to popular belief, today it's adults—not children—who most often contract invasive pneumococcal disease (IPD) . Why? Because children are effectively vaccinated. For years, pneumococcal vaccinations have been part of the mandatory childhood vaccination schedule, which has yielded tangible results—infection rates in this age group have dropped dramatically.

But IPD did not disappear – it just moved to older age groups.

Following the COVID-19 pandemic, we are seeing an increase in IPD cases. There are two reasons:

1. Better diagnosis and reporting of infections.

2. The so-called "rebound effect" after the pandemic – more social contacts, fewer masks, more opportunities for bacterial transmission.

But that's not all. More and more cases are caused by serotype 19A – particularly dangerous because it is multidrug-resistant . Treating such infections is becoming a huge challenge. Currently, as many as 13% of pneumococcal infections in Poland are caused by multidrug-resistant strains .

What can we do? Prevention is our most effective weapon. Based on epidemiological data—infection rates, predominant serotypes, and risk groups—we should select appropriate pneumococcal vaccines.

These are the recommendations of the World Health Organization (WHO), as well as European and Polish medical societies. Modern multivalent vaccines are available on the market that protect against the widest range of serotypes, including the most resistant ones.

In an age of aging populations and growing antibiotic resistance, we cannot afford to ignore preventive care. Pneumococcal vaccination should be standard care for people over 65 and patients with chronic diseases.