Sept 8 (Reuters) - Pfizer ( PFE ) and partner BioNTech

said on Monday their updated COVID-19 vaccine showed

an increased immune response in adults aged 65 and older as well

as those aged 18 through 64 with at least one underlying risk

condition.

Preliminary data from an ongoing late-stage trial showed at

least a four-fold increase in levels of LP.8.1-neutralizing

antibody after receiving the updated COVID-19 vaccine, the

companies said.

A total of 100 adults were enrolled in the trial.

This study was conducted to provide additional

information about immunological effects of the vaccine and is

not intended to replace the post-marketing commitments requested

by the U.S. health regulator.