Pneumococcal disease is a serious infection caused by the bacterium Streptococcus pneumoniae, also known as Pneumococcus. This bacterium is responsible for several life-threatening illnesses, including pneumonia, meningitis, and bacteraemia.
Additionally, it can lead to less severe but still significant conditions such as ear and sinus infections. Collectively, these infections are categorized as invasive pneumococcal disease (IPD), which can pose a major health risk, particularly to specific vulnerable populations.
Extent of the Problem
Pneumococcal disease is a global health concern, and its impact has been studied extensively. Data from the United States in 2017 revealed that the incidence of IPD was 2.5 cases per 100,000 people in the 18-34 year age group.
However, the risk increased dramatically with age, reaching 41.8 cases per 100,000 among individuals aged 85 or older. The most significant complication caused by Streptococcus pneumoniae is pneumonia, which continues to have a high incidence rate and is a major contributor to mortality, particularly among elderly individuals.
Studies conducted in the United States have demonstrated that 1 in 20 individuals who contract pneumococcal pneumonia will succumb to the disease. Similarly, pneumococcal meningitis is a potentially fatal condition that can result in severe long-term consequences for those who survive.
Survivors may suffer from epilepsy, blindness, hearing loss, and even paralysis. Another particularly severe manifestation of pneumococcal infection is pneumococcal bacteraemia, which can be extremely difficult to manage.
Those affected may require prolonged hospitalization, sometimes for weeks or even months, depending on the severity of their condition and the complications that arise.
Research from India has also highlighted the severity of pneumococcal infections. A 15-year surveillance study investigating invasive bacterial infections found that pneumococcal infections accounted for 43.3% (449 out of 1037) of cases.
The case fatality rate of pneumococcal disease across various adult age groups was estimated to be between 25% and 30%, reinforcing the significant threat posed by this infection.
Who is at Risk?
While anyone can contract pneumococcal disease, certain groups are particularly vulnerable to severe illness. Infants and young children under the age of five are at higher risk of developing pneumococcal infections.
Similarly, older adults, particularly those aged 65 and above, are more susceptible to complications arising from the disease. Other high-risk groups include adults with chronic health conditions such as heart, lung, kidney, or liver diseases.
Individuals diagnosed with diabetes, cerebrospinal fluid leaks, cochlear implants, HIV infection, cancer, or those who have undergone solid organ transplants are also at increased risk.
Furthermore, individuals on immunosuppressive medications and those with specific blood disorders, such as sickle cell disease, are more prone to developing pneumococcal infections. Individuals with damaged spleens or those who have undergone splenectomy (removal of the spleen) are particularly vulnerable.
Among lung diseases, chronic obstructive pulmonary disease (COPD) and asthma are commonly associated with a higher risk of pneumococcal infections. Lifestyle factors also play a role in increasing susceptibility.
Alcoholics and smokers have been found to have an elevated risk of contracting the disease due to their weakened immune systems and the damage inflicted on their respiratory tract.
An Indian study identified several key risk factors for pneumococcal infections in the Indian population. These included COPD, hypertension, diabetes, advanced age, and smoking.
The presence of multiple risk factors further exacerbates the likelihood of developing pneumococcal disease, a phenomenon referred to as risk stacking. A study from Germany found that individuals with three or more risk factors had a three- to four-fold higher likelihood of contracting pneumonia compared to those with fewer or no risk factors.
Usefulness of Vaccination
The development and widespread use of pneumococcal vaccines have significantly reduced the incidence of invasive pneumococcal disease (IPD) in both adults and children. Currently, two primary types of pneumococcal vaccines are available in India.
The first is the 23-valent pneumococcal polysaccharide vaccine (PPSV23), which has been in use for a considerable period. The second, more recently developed, is the 13-valent pneumococcal conjugate vaccine (PCV13).
While both vaccines are highly effective in preventing IPD, certain studies suggest that PCV13 may provide better immunity compared to PPSV23.
In addition to these vaccines, advancements in pneumococcal immunization continue to be made. More advanced vaccines, such as PCV21, are currently available in international markets and are expected to be introduced in India later this year.
The availability of improved vaccines further enhances the ability to protect at-risk individuals from pneumococcal disease.
Given the severe complications associated with pneumococcal infections, individuals with risk factors should undergo a comprehensive medical assessment to determine their eligibility for vaccination.
Healthcare professionals can provide counselling regarding the benefits of immunization and recommend the most suitable vaccine based on a patient’s medical history and specific risk factors.
Pneumococcal disease remains a major health concern, particularly for young children, elderly individuals, and those with underlying medical conditions. The infection can lead to severe complications such as pneumonia, meningitis, and bacteraemia, which can result in long-term disability or even death.
However, the introduction of pneumococcal vaccines has significantly lowered the burden of the disease. Vaccination plays a crucial role in preventing these serious infections and protecting those who are most vulnerable.
Individuals at risk should not overlook the importance of vaccination. Consulting a healthcare provider and receiving the appropriate pneumococcal vaccine can be a life-saving decision.
As medical advancements continue to improve vaccine efficacy, greater access to newer vaccines will further strengthen efforts to combat pneumococcal disease. By taking proactive steps, individuals can safeguard their health and reduce the risk of severe pneumococcal infections.