Background/Purpose:

Patients with rheumatoid arthritis (RA) are at an increased risk of some serious vaccine-preventable infections, like Pneumococcal infections. Since 2013, French vaccine recommendations committee considered as the best strategy for immune-suppressed patients, previously vaccinated by one dose of 23-valent pneumococcal polysaccharide vaccine (PPV23), a prime-boost revaccination strategy three years later. We evaluated in a pilot study the immunogenicity of the prime-boost revaccination strategy using PCV13 vaccination followed by PPV23 vaccination 8 weeks later in 24 patients with Rheumatoid Arthritis (RA) treated by Methotrexate (MTX) and anti-TNF. The persistence of a protective immunity for two years after revaccination was also evaluated in our population.

Methods:

Twenty-four patients with RA threated by MTX + anti-TNF were included after having received one dose of PCV13 (Prevenar13â; Pfizer) followed two months later by one dose of PPV23 (Pneumovax®, Merck) during routine-visits according to recommendations. All patients received a previous vaccination by the PPV23, at least three years before enrolment. Blood samples were obtained at baseline, 4 months, 12 months and 24 months following PCV13 immunization. Concentrations of IgG specific for 10 serotypes (7 common to both vaccines: 4, 6B, 9V, 14, 18C, 19F and 23F, and 3 uncommon, included only in the PPV23: 10A, 12F and 15B) were measured by standardized ELISA. Responders were defined as at least an IgG-concentration two fold increased from baseline by ELISA. An IgG-concentration ≥ 1.3µg/ml was used to defined long-term protection and Protected patients were those who fulfilled this criteria for at least 70% of the serotypes. Primary endpoint was the proportion of responders in ELISA for 70% of serotypes at four months.

Results:

Long term follow-up of antibody response to the vaccine shows a more severe decrease in the percentage of responders one and two years post immunization for the 7 common serotypes (from 33% responders at four months to 4% at 12 months and 3% at 24 months post immunization) compared to the 3 uncommon (from 47% responders at 4 months to 24% at 12 months and 23% at 24 months post immunization). As all patients received at least 3 years before enrolment one dose of PPV23, we found 33% (7 common serotypes) and 24% (3 uncommon serotypes) of patients considered protected at baseline. Similar percentages of protection were found at 4 months (63% vs. 65%), 12 months (54% vs. 59%) and 24 months (50% vs. 77%) for the 7 common and 3 uncommon serotypes.

Conclusion:

If the percentage of protection is quite equivalent for the seven common and the three uncommon serotypes, the more intense drop in antibody response for the seven common serotype compared to the three uncommon may suggest a negative impact of the PPV23 vaccine on the PCV13 response. The prime-boost strategy is recommended because of the poor immunogenicity of both type of pneumococcal vaccine in this case. Our results clearly question the advantage of the prime-boost strategy versus PPV23 or PCV13 alone as it highlight the possible hyporesponse induced by PPV23 against the immune response elicited by the primo-injection of the PCV13 vaccine.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/immunogenicity-and-persistence-of-a-prime-boost-re-vaccination-strategy-for-pneumococcal-vaccines-13-valent-pneumococcal-conjugate-vaccine-23-valent-pneumococcal-polysaccharide-vaccine-in-patients/