338. Influenza Vaccine is Protective Against Laboratory-Confirmed Influenza in Obese Children
Session: Poster Abstract Session: Influenza Vaccine in Children and Adults
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Background:

In adults hospitalized with influenza during the 2009 H1N1 influenza pandemic, obesity (body mass index (BMI) ≥ 30) was associated with increased risk of viral pneumonitis and admission to the intensive care unit. Extreme obesity (BMI > 40) was associated with greater odds of death.

This study evaluated if influenza vaccine is protective against disease in obese children and if unvaccinated obese children have higher rates of laboratory-confirmed influenza and absenteeism during influenza season compared to non-obese children.

Methods:

Active surveillance for influenza-like illness (ILI) was conducted on 4455 children from eight elementary schools (grades K-6) in Los Angeles County during the 2010-2011 season. Information collected included age, gender, height, weight, ethnicity, vaccination status, symptoms and duration of illness.  Obesity was defined as BMI ≥ 95th percentile.  Laboratory confirmation with multiplex polymerase chain reaction (PCR) for 12 respiratory viruses was performed on nose and throat swabs collected from children with ILI.

Results:

Of 4312 children with BMI data, 1191 (27.6%) were obese, and of these, 237 (19.9%) received vaccine. Of the 3121 (72.4%) non-obese children, 601 (19.3%) received vaccine.  ILI rates were similar in vaccinated and unvaccinated obese and non-obese children (21.7 vs. 19.5 per 100 children, p=0.104). Among vaccinated children, rates of PCR-confirmed influenza were similar in obese and non-obese children (1.7 vs. 2.0 per 100 children, p=0.769). In unvaccinated children, rates of PCR-confirmed influenza were higher in obese than non-obese children, but the values did not reach statistical significance (6.2 vs. 5.4 per 100 children, p=0.391). However, unvaccinated obese children were 3.8 times more likely to have PCR-confirmed influenza compared to vaccinated obese children (6.2 vs. 1.7 per 100 children, p=0.006) and miss more days of school (4.6 vs. 3.2 per 100 school days, p<0.001). Unvaccinated non-obese children were 2.8 times more likely to have PCR-confirmed influenza compared to vaccinated non-obese children (5.4 vs. 2.0 per 100 children, p<0.001) and miss more days of school (4.1 vs. 2.7 per 100 school days, p<0.001).

Conclusion:

Influenza vaccination protected both obese and non-obese children against laboratory-proven influenza illness and improved school attendance.

Michael Smit, MD, MSPH1, Noel Barragan, MPH2, Hailin Wang, MPH3, Laurene Mascola, MD, MPH2, Alvin Nelson El Amin, MD, MPH2, Grace Aldrovandi, MD, PhD3,4 and Pia Pannaraj, MD, MPH3,4, (1)Division Of Infectious Diseases, Children's Hospital Los Angeles, Los Angeles, CA, (2)Los Angeles County Department of Public Health, Los Angeles, CA, (3)Division of Infectious Diseases, Children's Hospital Los Angeles, Los Angeles, CA, (4)Keck School of Medicine, University of Southern California, Los Angeles, CA

Disclosures:

M. Smit, None

N. Barragan, None

H. Wang, None

L. Mascola, None

A. Nelson El Amin, None

G. Aldrovandi, None

P. Pannaraj, None

Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.