Pfizer has commenced a new study analysing the co-administration of a booster dose of its Covid-19 vaccine followed by its 20-valent pneumococcal conjugate vaccine (20vPnC) candidate in adults aged 65 years and above.

All initial participants enrolled in the trial have been immunised with the vaccines, Pfizer noted.

Being developed in alliance with BioNTech, the Covid-19 vaccine received an emergency use authorization from the US Food and Drug Administration (FDA) for active immunisation to prevent Covid-19 in people aged 12 and older.

Pfizer is developing the 20vPnC candidate to prevent invasive disease and pneumonia due to 20 serotypes of Streptococcus pneumoniae in adults aged 18 and older.

The vaccine candidate contains capsular polysaccharide conjugates for the 13 serotypes in Prevnar 13 (Pneumococcal 13-valent Conjugate Vaccine [Diphtheria CRM197 Protein]).

It also includes capsular polysaccharide conjugates for seven other serotypes that lead to pneumococcal disease and are linked to high case-fatality rates, antibiotic resistance, and/or meningitis.

In December 2020, the FDA agreed to a priority review of 20vPnC’s biologics licence application.

The European Medicines Agency also accepted to review the marketing authorisation application for the pneumococcal conjugate vaccine in adults in February.

Pfizer’s new trial will enrol 600 adult subjects from its Phase III Covid-19 vaccine trial.

These participants will have received the second dose of the vaccine a minimum of six months before moving into the latest combination study, Pfizer added.

The primary goal of the trial is the safety of co-administrating the vaccines, with a six-month follow-up after inoculation. Assessing immune responses generated by the vaccines will form the trial’s secondary goals.

A third dose of the Covid-19 vaccine will be administered to some participants as a booster dose.

Subjects in the trial will be given 20vPnC plus Covid-19 vaccine booster, 20vPnC plus placebo, or Covid-19 vaccine booster plus placebo.