- Vaccines can prevent some bacterial infections that cause pneumonia and meningitis
- Researchers reviewed cases of invasive pneumococcal disease in Alberta and Ontario
- Of patients who survived an initial episode of IPD, only 22% were vaccinated to prevent another
Certain bacteria, such as S. pneumoniae, can temporarily live in the nasal passages or throat. The bacteria are spread when a person inhales droplets from an infected person. Contact can occur because of sneezing, coughing or talking. According to the Public Health Agency of Canada, contact can also occur by “touching objects that were recently exposed to an infected person’s mucus or saliva (such as shared utensils, cups, tissues and toys) then rubbing your eyes, nose or mouth.”
Some conditions (such as influenza, chronic lung disease, chronic kidney disease, chronic liver disease, cardiovascular disease and immune deficiencies) and factors (such as exposure to cigarette smoke) can make people susceptible to disease caused by S. pneumoniae. In such cases, the bacteria can attack the lungs or gain entry to the blood (become invasive) and attack organs such as the lungs and lining of the brain. Invasive pneumococcal disease (IPD) can cause serious complications and in some cases death. Public subsidies are available in Canada for vaccines to prevent IPD.
In Alberta and Ontario
Researchers in Alberta and Ontario have reviewed data on IPD in adults in their respective regions. The team of researchers looked at cases of recurrent IPD and populations at risk for this disease.
Between 2004 and 2022, the researchers found that 7,006 adults survived an initial (primary) episode of IPD. Of this population, about 4% (274 people) developed recurrent IPD.
On average, among people with recurrent IPD, 61% were assigned male at birth and 39% were assigned female at birth. The average age of people with recurrent IPD was 54 years.
Statistical analysis found that the following factors were linked to a significantly increased risk for recurrent IPD (listed in decreasing order):
- a history of stem cell transplant or having certain cancers such as lymphoma or leukemia
- HIV infection
- experiencing homelessness
- alcohol use disorder
Researchers found that at the primary episode of IPD, 88% of participants were eligible for pneumococcal vaccination but only 28% had been vaccinated.
At the second episode of IPD, 73% were eligible for vaccination but only 22% had been vaccinated.
The proportions of people who died were as follows:
- within the first month after a first episode of IPD – 16%
- after the first recurrence of IPD – 12%
- after the second recurrence of IPD – 15%
- after the third recurrence of IPD – 22%
Bear in mind
As with all studies, there is room for improvement in the present study. For instance, some data were missing: 12% of participants lacked data for prior vaccination and 12% lacked data for smoking history. This missing data occurred in Alberta and Ontario. Also, there were no data on deaths due to other causes. Nevertheless, the study underscores the case for healthcare providers to encourage their patients to get vaccinated against IPD. In some instances, such as in populations experiencing homelessness, outreach by mobile teams of health personnel may be necessary.
Reducing risk for IPD
In addition to vaccines to increase protection against S. pneumoniae, strategies that address underlying risk factors may be useful, such as the following:
- getting help with smoking cessation
- regular vaccination against the flu
- improved management of issues such as diabetes, cardiovascular disease, kidney disease, liver disease and HIV infection
—Sean R. Hosein
Resources
Invasive Pneumococcal Disease – Public Health Agency of Canada
Pneumococcal vaccines: Canadian Immunization Guide – Public Health Agency of Canada
REFERENCES:
- Ricketson LJ, Shigayeva A, Rajakumar I, et al. Incidence of recurrent invasive pneumococcal disease in Canada. JAMA Network Open. 2026 Jul 1;9(7):e2621797.
- Goldblatt D, O’Brien KL. Chapter 151. Pneumococcal infections. In: Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson JK, Loscalzo J, Holland SM, Langford CA. Harrison’s Principles of Internal Medicine, 22e New York, NY: McGraw-Hill; 2025.