ARE PNEUMONIA VACCINES EFFECTIVE?
The CDC recommends that everyone get a pneumonia vaccine at some point, but there is little evidence supporting their efficacy
Straight Healthcare
November 2024
On June 17, 2024, the FDA approved the pneumococcal vaccine Capvaxive (PCV21), bringing the number of available adult pneumonia vaccines to five. Months later, the CDC lowered the recommended age for pneumococcal vaccination in average-risk adults from 65 to 50. With so many vaccine options and a CDC recommendation for universal vaccination, one might assume pneumonia vaccines have robust data backing their effectiveness. However, the evidence supporting their use is surprisingly limited. Below, we review the available vaccines, their recommended schedules, and clinical trials evaluating their efficacy.
So, just how effective are pneumococcal vaccines? There is no real-world data on the three newer vaccines (PCV20, PCV15, PCV21), as their approvals were based on antibody titers, a surrogate endpoint. The largest randomized controlled trial evaluating the efficacy of pneumococcal vaccines was performed in the Netherlands, where 84,496 adults aged 65 or older (mean age 73 years) were randomized to PCV13 or placebo. After an average follow-up of 3.97 years, 0.32% of patients who received PCV13 had confirmed pneumococcal community-acquired pneumonia (CAP) compared to 0.41% in the placebo group (p=0.05). The PCV13 group had a lower incidence of CAP caused by pneumococcal strains covered in the vaccine (0.15% vs 0.25%, p=0.003), but there was no significant difference in overall cases of CAP (1.8% vs 1.9%, p=0.32) or all-cause mortality (7.1% vs 7.1%). [PubMed abstract]
As for PPSV23, no large randomized trials involving the general public have been published. Small studies examining its effects in high-risk patients have been mostly disappointing - PMID 28122642, PMID 9482293, PMID 20211953, PMID 10902624.
Vaccine approvals translate to big bucks for pharmaceutical companies, especially if the vaccine becomes part of the CDC's routine schedule, which means millions of people will receive it each year without question when their provider recommends it; not to mention, many providers are "graded" on their patient's vaccination status by Medicare and other healthcare entities.
There is no question vaccines save lives, but in some cases, the overall benefit is debatable, and it seems fair to question recommendations that call for the routine vaccination of large populations. Unless PCV20, PCV15, and PCV21 prove to be far superior to PCV13, we will have three more vaccines with questionable benefits.
- Pneumovax (PPSV23) - PPSV23 is a vaccine from Merck available since 1983 that covers 23 serotypes of Streptococcus pneumoniae.
- Prevnar 13 (PCV13) - PCV13 is a conjugate vaccine from Pfizer that covers 13 serotypes of Streptococcus pneumoniae. PCV13 has been available since 2010 and is part of the recommended childhood immunization schedule. In adults, the CDC used to recommend all people 65 and older routinely receive PCV13 and PPSV23. In 2019, they dropped PCV13 from the recommendation because its use in children led to a sharp decline in pneumococcal disease among adults.
- Prevnar 20 (PCV20) - PCV20 is a conjugate vaccine from Pfizer approved in 2021 that covers 20 serotypes of Streptococcus pneumoniae
- Vaxneuvance (PCV15) - PCV15 is a conjugate vaccine from Merck approved in 2021 that covers 15 serotypes of Streptococcus pneumoniae
- Capvaxive (PCV21) - PCV21 is a conjugate vaccine from Merck approved in 2024 that covers 21 serotypes of Streptococcus pneumoniae
- CDC recommendations in adults ≥ 50 years
- One dose of PCV15, PCV20 or PCV21. If PCV15 is used, a dose of PPSV23 is recommended a year later.
- Indications for early vaccine - see CDC pneumococcal vaccine advisor
So, just how effective are pneumococcal vaccines? There is no real-world data on the three newer vaccines (PCV20, PCV15, PCV21), as their approvals were based on antibody titers, a surrogate endpoint. The largest randomized controlled trial evaluating the efficacy of pneumococcal vaccines was performed in the Netherlands, where 84,496 adults aged 65 or older (mean age 73 years) were randomized to PCV13 or placebo. After an average follow-up of 3.97 years, 0.32% of patients who received PCV13 had confirmed pneumococcal community-acquired pneumonia (CAP) compared to 0.41% in the placebo group (p=0.05). The PCV13 group had a lower incidence of CAP caused by pneumococcal strains covered in the vaccine (0.15% vs 0.25%, p=0.003), but there was no significant difference in overall cases of CAP (1.8% vs 1.9%, p=0.32) or all-cause mortality (7.1% vs 7.1%). [PubMed abstract]
As for PPSV23, no large randomized trials involving the general public have been published. Small studies examining its effects in high-risk patients have been mostly disappointing - PMID 28122642, PMID 9482293, PMID 20211953, PMID 10902624.
Vaccine approvals translate to big bucks for pharmaceutical companies, especially if the vaccine becomes part of the CDC's routine schedule, which means millions of people will receive it each year without question when their provider recommends it; not to mention, many providers are "graded" on their patient's vaccination status by Medicare and other healthcare entities.
There is no question vaccines save lives, but in some cases, the overall benefit is debatable, and it seems fair to question recommendations that call for the routine vaccination of large populations. Unless PCV20, PCV15, and PCV21 prove to be far superior to PCV13, we will have three more vaccines with questionable benefits.
