From the Guidelines
Immunologists check for immunity to the pneumonia shot at two weeks because this timeframe allows for optimal assessment of the immune response, as indicated by a study from 1997 1, which suggests that an antigen-specific antibody response develops within 2-3 weeks in greater than or equal to 80% of healthy young adults.
Key Points
- The two-week mark represents a critical point when antibody levels have typically reached detectable and meaningful levels after receiving a pneumococcal vaccine.
- During this period, B cells have had sufficient time to recognize the vaccine antigens, proliferate, and differentiate into antibody-producing plasma cells.
- The antibody levels measured at this point provide valuable information about whether the vaccine has successfully stimulated the immune system and whether the patient has developed adequate protection against pneumococcal disease.
- If antibody levels are insufficient at this checkpoint, healthcare providers may consider additional doses or alternative vaccination strategies, especially for immunocompromised patients who might have impaired immune responses.
Recent Guidelines
A more recent study from 2024 1 provides updated guidelines for the prevention and treatment of cancer-related infections, including the use of pneumococcal vaccines, but does not specifically address the timing of immunity checks.
Evidence Summary
The evidence suggests that checking for immunity to the pneumonia shot at two weeks is a reasonable approach, as it allows for optimal assessment of the immune response and timely clinical decision-making about the patient's protection status, as supported by studies from 1997 1 and 2010 1.
From the Research
Immunological Response to Pneumococcal Vaccine
- The pneumococcal conjugate vaccine induces a T-cell dependent immune response, which provides an extended duration of protection with repeated vaccinations 2.
- Immunogenicity studies have demonstrated successful responses in children with sickle cell disease and human immunodeficiency virus infection 3.
- The vaccine's effectiveness in healthy children against invasive pneumococcal disease, as well as against pneumonia and otitis media, has been demonstrated in an efficacy trial involving nearly 38,000 subjects 3.
Timing of Immunity Check
- The US Advisory Committee on Immunization Practices (ACIP) recommends that infants receive the vaccine routinely at 2,4, and 6 months with a fourth dose at 12 to 15 months of age 3.
- Infants may receive the first dose as early as 6 weeks of age 3.
- However, there is no specific evidence in the provided studies to support checking for immunity to the pneumococcal vaccine at exactly two weeks.
Antibody Response
- Studies have shown that antibody levels after pneumococcal vaccination persist above concentrations in unvaccinated adults for at least 5-10 years in most studies 4.
- Revaccination with PPSV23 5-10 years after a previous dose consistently and substantially increases both IgG and functional antibody levels 4.
- The median concentrations for all ages 6 years post-vaccination were significantly elevated compared to the pre-vaccination titres for PPV IgA, IgG, and IgG2 isotypes only 5.