Pfizer Inc said on Wednesday booster doses of its COVID-19 vaccine can be administered along with its pneumonia vaccine and produced strong safety and immune responses in people aged 65 and above in a late-stage study.

The study, initiated in May, tested the company's next-generation pneumococcal conjugate vaccine, PREVNAR 20, with a third dose of the Pfizer-BioNTech COVID-19 shot in 570 participants.

The aim of the study was to test the safety of the combination and the immune response after adding the pneumonia vaccine to the existing COVID-19 vaccine.

The company said responses elicited by PREVNAR 20 and booster dose of the COVID-19 vaccine were similar when given together or with placebo.

The data provides evidence supporting the potential to administer PREVNAR 20 and the company's COVID-19 vaccine at the same time, reducing the number of visits people make to doctors or pharmacies for recommended immunization, Pfizer said.

PREVNAR 20 was approved by the U.S. Food and Drug Administration in June last year to help protect adults against most invasive pneumococcal diseases and pneumonia.

Study participants were recruited from the companies' late-stage COVID-19 vaccine study, and those who had received the second dose of the company's COVID-19 vaccine at least six months before entering the co-administration study.