Human respiratory syncytial virus and other viral infections in infants receiving palivizumab.
BACKGROUND
Palivizumab is a humanized monoclonal antibody that prevents severe human respiratory syncytial virus (HRSV) infections.


OBJECTIVE
We determined the etiology of respiratory viral infections in palivizumab recipients, and monitored the clinical outcome and HRSV genotype in HRSV-infected infants.


METHODS
Nasopharyngeal aspirates (NPAs) were collected from children receiving palivizumab who consulted or were hospitalized for acute respiratory tract infection (ARTI) during the 2004-2005 season. Viral cultures and multiplex RT-PCR for influenza A/B, HRSV and human metapneumovirus were performed. The fusion (F) gene of HRSV amplicons was also sequenced.


RESULTS
Among 116 enrolled patients, 51 (44%) had > or = 1 episode of ARTI for a total of 93 visits. At least one virus was identified in 33 (36%) of the 93 NPA samples; HRSV accounted for 11 (33%) of confirmed viral etiologies. Compared to subjects who had other viral ARTI, HRSV-positive subjects had less fever (p=0.01) and tended to have more bronchiolitis (p=0.07). Ten subjects (11 visits) developed HRSV infection, although only one was hospitalized. HRSV was detected after a median of 5.5 palivizumab doses and a median of 14 days after the last dose. One of the 11 HRSV strains tested had a F mutation located in the palivizumab-binding site.


CONCLUSIONS
HRSV is still a major cause of ARTI in children receiving palivizumab, although the outcome of infected children appears mild.
Boivin
Guy
G
Research Center in Infectious Diseases, CHUQ-CHUL, Québec City, QC, Canada. Guy.Boivin@crchul.ulaval.ca
Caouette
Georges
G
Frenette
Line
L
Carbonneau
Julie
J
Ouakki
Manale
M
De Serres
Gaston
G
D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000998:Antiviral Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007223:Infant; D009980:Influenza A virus / Q000302:isolation & purification; D009981:Influenza B virus / Q000302:isolation & purification; D008297:Male; D029121:Metapneumovirus / Q000302:isolation & purification; D009305:Nasopharynx / Q000821:virology; D000069455:Palivizumab; D012367:RNA, Viral / Q000235:genetics; D018113:Respiratory Syncytial Virus, Human / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000188:drug therapy* / Q000503:physiopathology / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA; D014777:Virus Diseases / Q000188:drug therapy* / Q000503:physiopathology / Q000821:virology*
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000998:Antiviral Agents; D012367:RNA, Viral; D000069455:Palivizumab