Published online May 2, 2005
PEDIATRICS Vol. 115 No. 5 May 2005, pp. 1439-1440 (doi:10.1542/peds.2004-2865)

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Optimal Timing and Dosing Intervals of Palivizumab in Premature Neonates: Still Some Work to Do

Paolo Manzoni, MD
Ugo Sala, MD
Giovanna Gomirato
Neonatology and Hospital NICU
S. Anna Hospital
Azienda Ospedaliera OIRM-S. Anna
University of Turin
10136 Turin, Italy

Alessandra Coscia, MD
Claudio Fabris
Cattedra di Neonatologia
University of Turin
10136 Turin, Italy

To the Editor.—

We read with great interest the Pediatrics article published by Wu et al,¹ which showed that very premature infants had sustained optimal protective levels of palivizumab (>40 µg/mL) serum concentrations only after the second dose, and up to 77% of the infants tested had no protective concentrations before the second dose. Because the ability of premature neonates to achieve efficient protection against respiratory syncytial virus (RSV) infection relies on serum palivizumab concentrations, one should suspect a considerable rate of inefficacy of palivizumab (in its currently recommended schedule) in preventing RSV infections in the first month of administration and, similarly, a con siderable rate of uncertainty of protection in the subsequent months, particularly in the days preceding the new administration.

The authors correctly claim that "[a]dditional studies are needed to establish the optimal timing of the initial dose and optimal dosing interval of palivizumab in this most vulnerable population"; thus, we briefly describe our experience that shows the clinical impact of the data provided by Wu et al and the opportunity for reconsidering some issues with the current prophylactic schedule.

In our 2 third-level units, which attends to a mean of 9000 births per year, we treated 389 infants at risk with palivizumab in the last 4 epidemic seasons. Infants were enrolled following the recommendations of the Italian Society of Pediatrics,^2,3 fully implementing in Italy the American Academy of Pediatrics guidelines⁴; palivizumab, 15 mg/kg per dose intramuscularly, was administered every 28 days in the months from October to April. Compliance to recruitment was very high (96.8%), and 91.1% of the infants completed the scheduled course (5–6 monthly administrations). The overall incidence of RSV-related hospitalizations was very low (9 infants [2.3%]). It is notable that all episodes occurred between the 19th and 23rd days after the previous administration: 5 of them occurred after the second dose, and 4 occurred after the third dose, always during the epidemic peak. No fatal event occurred.

Our experience underlines the fact that, despite achieving high compliance rates, the efficacy of palivizumab administered by following the currently recommended schedule is not satisfactory (all RSV-positive admissions in our series occurred when palivizumab serum concentrations, according to the study of Wu et al, had probably dropped under the optimal range) and probably could be improved by modifying the schedule (increasing the doses in the first and second courses and/or shortening the intervals between courses during the epidemic peak). In our opinion, efforts to improve the efficacy of palivizumab should be increased, not only to improve compliance but also to prevent failures related to less-than-optimal timing and dosing, which are frustrating after the hard work that was needed to achieve optimal compliance.

REFERENCES

1. Wu S-Y, Bonaparte J, Pyati S. Palivizumab use in very premature infants in the neonatal intensive care unit. Pediatrics. 2004;114(5) . Available at: www.pediatrics.org/cgi/content/full/114/5/e554
2. American Academy of Pediatrics, Committee on Infectious Diseases and Committee of Fetus and Newborn. Prevention of respiratory syncytial virus infections: indications for the use of palivizumab and update on the use of RSV-IGIV. Pediatrics. 1998;102 :1211 –1216[Abstract/Free Full Text]
3. Meissner HC, Long SS; American Academy of Pediatrics, Committee on Infectious Diseases and Committee on Fetus and Newborn. Revised indications for the use of palivizumab and respiratory syncytial virus immune globulin intravenous for the prevention of respiratory syncytial virus infections. Pediatrics. 2003;112 :1447 –1452[Abstract/Free Full Text]
4. Società Italiana di Neonatologia. Raccomandazioni per la prevenzione della malattia da virus respiratorio sinciziale (RSV). Riv Ital Pediatr. 2000;26 :379 –381

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PEDIATRICS (ISSN 1098-4275). ©2005 by the American Academy of Pediatrics

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This Article Extract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services E-mail this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Manzoni, P. Articles by Fabris, C. Search for Related Content PubMed PubMed Citation Articles by Manzoni, P. Articles by Fabris, C. Related Collections Infectious Disease & Immunity Social Bookmarking                         What's this?