Pneumococcal coinfection with human metapneumovirus.

Area of Science:

• Pediatrics
• Infectious Diseases
• Vaccinology

Background:

• Human metapneumovirus (hMPV) is a newly discovered virus causing lower respiratory tract infections (LRTI) in children.
• The pathogenesis of hMPV-associated LRTI leading to hospitalization remains unclear.
• Bacterial coinfection is suspected in hMPV pathogenesis.

Purpose of the Study:

• To investigate the role of bacterial coinfection in hMPV-associated LRTI.
• To determine if pneumococcal conjugate vaccine (PCV) can prevent hMPV-associated LRTI and pneumonia.
• To evaluate the efficacy of PCV in both HIV-uninfected and HIV-infected children.

Main Methods:

• A cohort study involving children hospitalized with LRTI.
• Participants were randomized to receive 9-valent conjugate pneumococcal vaccine or placebo.
• hMPV infection was detected using a nested reverse-transcription polymerase chain reaction assay targeting the F protein gene.

Main Results:

• Among HIV-uninfected children receiving PCV, hMPV-associated LRTI incidence decreased by 45% (P = .002) and pneumonia by 55% (P = .003).
• In fully vaccinated HIV-infected children, hMPV-associated LRTI incidence decreased by 53% (P = .035) and pneumonia by 65% (P = .020).
• These reductions indicate a significant protective effect of PCV against hMPV-related respiratory illness.

Conclusions:

• The pathogenesis of hMPV-associated LRTI involves bacterial coinfection with Streptococcus pneumoniae.
• Pneumococcal conjugate vaccine (PCV) significantly reduces hMPV-associated LRTI and pneumonia in hospitalized children.
• PCV vaccination can prevent a substantial proportion of hMPV-related hospitalizations in both HIV-infected and HIV-uninfected children.