Department of Research & Evaluation News

One type of pneumonia vaccine, the PCV13 vaccine, may affect the course of COVID-19 for some older adult patients, new research shows. The Kaiser Permanente study was published in The Journal of Infectious Diseases.

“Kaiser Permanente members who received the PCV13 vaccine appeared to be diagnosed with COVID-19 less often, and when they were, they seemed to have less severe outcomes, overall,” said the senior author, Sara Y. Tartof, PhD, MPH, a scientist with the Kaiser Permanente Southern California Department of Research & Evaluation. “One of the most interesting aspects of our findings was that the patients who received PCV13 received some protection against COVID-19, while those who received PPSV23, another pneumococcal vaccine, did not.”

When the virus that causes COVID-19 infects a new person, it encounters a diverse array of viral and bacterial species that naturally reside in the human upper airway. One of these species is a bacterium called Streptococcus pneumoniae, or pneumococcus, which is commonly carried by children as well as adults. While typically harmless, this bacterium is well known for causing pneumonia and other diseases, often in interaction with viruses.

This new Kaiser Permanente study provides evidence that these bacterial-viral interactions may play out in ways that shape the course of COVID-19.

While the recently authorized COVID-19 vaccines remain the most important strategy for preventing COVID-19, investigators found that older adults who received pneumococcal conjugate vaccine (PCV13), which prevents acquisition of certain pneumococcal strains, experienced 35% lower risk of COVID-19 diagnosis than adults who did not receive the vaccine. In contrast, an alternative pneumococcal vaccine (PPSV23), which prevents severe pneumococcal disease but does not block acquisition of the bacterium, was not associated with protection.

This study examined electronic health records of 531,033 members of Kaiser Permanente in Southern California who were 65 years old and older from March 1 to July 22, 2020. Among that population, 3,677 had a COVID-19 diagnosis, 1,075 were hospitalized for COVID-19, and 334 died from COVID-19.

Among adults ages 65 years old and older, those who received the pneumonia vaccine PCV13 had:

• 35% lower incidence of COVID-19 diagnosis
• 32% lower incidence of COVID-19 hospitalization
• 32% lower incidence of COVID-19 death

Anyone can get pneumococcal disease, but children under 2 years of age, people with certain medical conditions, cigarette smokers, and adults aged 65 years or older are at the highest risk. The study’s authors only looked at older patients, who also face the highest risk of severe COVID-19.

PCV13 protects against 13 types of bacteria that cause pneumococcal disease. This vaccine is given to adults 65 years or older based on shared decision-making between the patient and health care provider, typically based on risk factors. These risk factors, which can include COPD, asthma, heart disease, are also factors that can put people at risk for COVID-19.

“Over the years we have learned that pneumococci interact with influenza, RSV, and several other viruses in the airway,” said lead author Joseph A. Lewnard, PhD, at the School of Public Health, University of California, Berkeley. “These observations with SARS-CoV-2 help to suggest that the phenomenon may be more general than we have previously appreciated.”

As with any research study, this one did have some limitations including that some of the early COVID-19 cases were identified by diagnostic codes in the electronic health records rather than laboratory tests, and that some other potential factors, such as the association between vaccine access and compliance with social distancing were not accounted for in the data.

This study was funded by Pfizer Inc. The Journal of Infectious Diseases received funding from the National Institute of General Medical Sciences (grant MIDASNI2020-3 under U24GM132013-02S2), the National Institute of Allergy and Infectious Diseases (grant R01-AI14812701A1), and the Berkeley Population Center, on behalf of the National Institute of Child Health and Human Development (grant P2CHD073964).

Other authors include Katia J. Bruxvoort, Heidi Fischer, and Vennis X. Hong from the Department of Research & Evaluation, Kaiser Permanente Southern California; and Lindsay R. Grant, Luis Jódar, and Bradford D. Gessner from Pfizer Vaccines.