The US drug regulator approved a second vaccine against respiratory syncytial virus (RSV), its American developer Pfizer said Wednesday, a month after the authorization of the first shot against the pathogen, a leading cause of lung infections.

The announcement comes only weeks after the regulator, the Food and Drug Administration, approved Arexvy from British drugmaker GSK -- the world's first RSV vaccine.

"Today's approval is a monumental step forward in delivering on Pfizer's commitment to help alleviate the significant burden of RSV in higher-risk populations, which includes older adults," Pfizer's head of vaccine research development Annaliesa Anderson said in a statement.

Abrysvo and GSK's Arexvy are both intended for people over the age of 60.

Officials from the US Centers for Disease Control and Prevention are set to meet June 21 to draw up recommendations for the administration of RSV vaccines in the elderly.

Pending that meeting, US-based Pfizer plans to introduce Abrysvo to the market in the third quarter, ahead of the expected fall surge in cases of bronchiolitis -- lung inflammation often caused by an RSV infection.

Pfizer has also sought approval for a vaccine meant for pregnant patients, who would then pass on the protection to their babies. An independent panel of experts recommended the adoption of that vaccine in mid-May, though the FDA has not yet issued a decision.

RSV is a widespread, highly contagious pathogen most known for causing bronchiolitis -- an irritation and inflammation of the small airways -- in young children, especially in winter.

It also infects adults and can become dangerous in the elderly, who may develop pneumonia.

According to US health officials, RSV kills between 6,000 and 10,000 people over age 65 in the United States every year, and causes between 60,000 and 160,000 hospitalizations.

And it sends between 58,000 and 80,000 children under the age of five to the hospital every year, according to the CDC.