Influenza Vaccine is Protective Against Laboratory-confirmed Influenza in Obese Children.

BACKGROUND: Obesity emerged as a novel risk factor for severe disease during the 2009 H1N1 influenza pandemic. Murine studies indicate that obesity is associated with ineffective response to influenza vaccine, but few human studies exist. We aimed to determine if influenza vaccine is protective against laboratory-confirmed influenza in obese children. METHODS: Body mass index, vaccination status, and laboratory-confirmed influenza data were analyzed from a previously conducted prospective study in which active surveillance for influenza-like illness was conducted in 8 elementary schools in Los Angeles County during the 2010-2011 influenza season. Polymerase-chain reaction (PCR) was performed on combined nose/throat swabs collected from children with influenza-like illness at presentation to the school nurse or during absenteeism. RESULTS: Of 4260 children with height/weight data, 1191 (28.0%) were obese (body mass index ≥95th percentile). Respiratory specimens were obtained from 858 (20.1%) children. Unvaccinated obese compared with vaccinated obese children acquired 3 times more PCR-confirmed influenza (62 vs. 17 per 1000 children, P = 0.003) and missed more school days (4.6 vs. 3.2 per 100 school days, P < 0.001) during influenza season. Obese children with PCR-confirmed influenza were more likely to present with cough (86.2 vs. 72.4%, P = 0.030) and missed more school per episode (2.4 vs.1.9 days, P = 0.023) compared with nonobese children. Among vaccinated children, rates of PCR-confirmed influenza were similar in obese and nonobese children (17 vs. 20 per 1000 children, P = 0.77). CONCLUSIONS: Obese children with PCR-confirmed influenza suffered from more cough and missed more school days than their nonobese peers. Influenza vaccination protected obese children against PCR-proven influenza illness.

Parental perceptions and predictors of consent for school-located influenza vaccination in urban elementary school children in the United States.

BACKGROUND: School-located influenza vaccination (SLV) programs have the potential to mass-vaccinate all enrolled children, but parental consent is required. OBJECTIVE: To examine parental attitudes and determine predictors of parental consent for vaccination of schoolchildren through SLV programs. PATIENTS/METHODS: Surveys were distributed to parents of 4517 children during 2009-2010 (year 1) and 4414 children during 2010-2011 (year 2) in eight elementary schools in conjunction with a SLV program. RESULTS: Participants included 1259 (27·9%) parents in year 1 and 1496 (33·9%) in year 2. Parental consent for 2009 H1N1, 2009 seasonal, and 2010 seasonal influenza vaccines was obtained from 738 (70·8%), 673 (64·5%), and 1151 (77·2%) respondents, respectively. During the 2009 pandemic, respondents concerned about influenza severity were twice as likely to consent for the 2009 H1N1 vaccination compared to unconcerned respondents (OR 2·04, 95% CI:1·19-3·51). During year 2, factors that predicted parental consent were the perception of high susceptibility to influenza infection (OR 2·19, 95% CI:1·50-3·19) and high benefit of vaccine (OR 2·23, 95% CI:1·47-3·40). In both years, college-educated parents were more likely to perceive vaccine risks (year 1: 83·6 versus 61·5%, P < 0·001 and year 2: 81·1% versus 60·6%, P < 0·001) and less likely to consent for seasonal influenza vaccine (year 1: OR 0·69, 95% CI:0·53-0·89 and year 2: OR 0·61, 95% CI:0·47-0·78) compared to non-college-educated parents. CONCLUSIONS: Parents who appreciate the risks of influenza and benefits of vaccination are more likely to consent for SLV. More research is needed to determine how to address heightened safety concerns among college-educated parents.

Varicella hospitalizations in Los Angeles during the varicella vaccination era, 2003-2011: are they preventable?

Characteristics of varicella-related hospitalizations in the mature varicella vaccination era, including the proportion vaccinated and the severity of disease, are not well described. We present the vaccination status, severity and reasons for hospitalization of the hospitalized varicella cases reported to the Los Angeles County Health Department from 2003 to 2011, the period which includes the last 4 years of the mature one-dose program and the first 5 years after introduction of the routine two-dose program. A total of 158 hospitalized varicella cases were reported overall, of which 52.5% were potentially preventable and eligible for vaccination, 41.8% were not eligible for vaccination, and 5.7% were vaccinated. Most hospitalizations (72.2%) occurred among healthy persons, 54.4% occurred among persons ≥20 years of age, and 3.8% of hospitalizations resulted in death. Our data suggest that as many as half of the hospitalized varicella cases, including half of the deaths, may have been preventable given that they occurred in persons who were eligible for vaccination. More complete implementation of the routine varicella vaccination program could further reduce the disease burden of severe varicella.

School-located influenza vaccination decreases laboratory-confirmed influenza and improves school attendance.

BACKGROUND: School-located influenza vaccination (SLV) programs can efficiently immunize large numbers of school-aged children. We evaluated the impact of SLV on laboratory-confirmed influenza and absenteeism. METHODS: Active surveillance for influenza-like illness (ILI) was conducted on 4455 children in 4 SLV intervention and 4 control elementary schools (grades K-6) matched for sociodemographic characteristics during the 2010-2011 influenza season in Los Angeles County, California. Combined nose/throat swabs were collected from febrile children with ILI at presentation to the school nurse or during absenteeism. RESULTS: In SLV schools, 26.9%-46.6% of enrolled students received at least 1 dose of either inactivated or live attenuated influenza vaccine compared with 0.8%-4.3% in control schools. Polymerase chain reaction for respiratory viruses (PCR) was performed on 1021 specimens obtained from 898 children. Specimens were positive for influenza in 217 (21.3%), including 2009 H1N1 (30.9%), H3 (9.2%), and B (59.9%). Children attending SLV schools, regardless of vaccination status, were 30.8% (95% confidence interval, 10.1%-46.8%) less likely to acquire influenza compared with children at control schools. Unvaccinated children were indirectly protected in the school with nearly 50% vaccination coverage compared with control schools (influenza rate, 27.1 vs 60.0 per 1000 children; P = .023). Unvaccinated children missed more school days than vaccinated children (4.3 vs 2.8 days per 100 school days; P < .001). CONCLUSIONS: Vaccination of at least a quarter of the school population resulted in decreased influenza rates and improved school attendance. Herd immunity for unvaccinated children may occur in schools with vaccination coverage approaching 50%.

Implementation of a hepatitis A/B vaccination program using an accelerated schedule among high-risk inmates, Los Angeles County Jail, 2007-2010.

BACKGROUND: The Centers for Disease Control and Prevention recommend vaccination for men who have sex with men (MSM) and injection drug users against hepatitis A and B. This study is the first report of a hepatitis vaccination program in a United States jail with a combined vaccine using an accelerated schedule. Los Angeles County has the largest jail system in the nation and Men's Central Jail (MCJ) is the largest facility within that system. MCJ includes a unit for self-identified MSM, where approximately 2700 inmates are housed per year. METHODS AND FINDINGS: Starting in August 2007, a combined hepatitis A and B vaccine was offered to all inmates housed in this special unit. Using an accelerated schedule (0-, 7-, 21-30 days, 12-month booster), a total of 3931 doses were administered to 1633 inmates as of June 2010. Of those, 77% received 2 doses, 58% received 3 doses, and 11% received the booster dose. Inmates who screened positive for a sexually transmitted infection in this unit were 1.3 times more likely to be vaccinated (95% CI 1.2-1.4) compared to others in the same housing unit who screened negative. CONCLUSIONS: Hepatitis vaccination initiatives can be successfully implemented in an urban jail among an extremely high-risk population using the accelerated, combined hepatitis A/B vaccine. Ours may be a useful model for other programs to vaccinate incarcerated populations.