February 2007 • www.pediatricnews.com Infectious Diseases 13 Top Findings in Pediatric Infectious Disease

BY DIANA MAHONEY acute respiratory tract infection or fever at er durations of intensive care (5.0 vs. 1.8 outbreaks of the disease in early 2006 in the New England Bureau clinics, emergency departments, and hos- weeks), mechanical ventilation (4.4 vs. 1.8 Midwestern United States, the ACIP up- pitals in three U.S. counties. They collect- weeks), and tube or intravenous feeding dated its 1998 criteria for mumps immuni- T ORONTO — Advances in the fight ed outpatient data during two influenza (10.6 vs. 3.6 weeks). Both type and fre- ty and mumps vaccination recommenda- against human bocavirus, infant botulism, seasons—2002-2003 and 2003-2004 (when quency of adverse events were similar in tions. Among the key changes, Dr. St. and severe rotavirus gastroenteritis were influenza vaccine was recommended for the two groups. Geme noted, were the criteria for accept- among the topics selected as the top new all children between 6 and 23 months)— In a subsequent open-label study that able presumptive evidence of immunity for findings in pediatric infectious disease at and inpatient data from 2000 to 2004. included 382 infants in 37 states, BIG-IV school-age children and adults at high risk, the annual meeting of the Infectious Dis- The average annual rate of hospitaliza- treatment within 3 days of admission sig- including those who work in health care fa- eases Society of America. tion associated with influenza was 0.9 per nificantly shortened mean length of hos- cilities, international travelers, and college “There has been a lot of activity in pe- 1,000 children in 2000-2004. The estimat- pital stay, compared with treatment with- students. “Previously, documentation of diatric infectious diseases, with some im- ed burden of outpatient visits associated in 4-7 days of admission: 2.0 vs. 2.9 weeks adequate vaccination for these populations portant observations over the past year with influenza was 50 clinic visits and 6 (N. Engl. J. Med. 2006; 354:462-71). was one dose of a live mumps virus vac- that will likely have an impact on clinical emergency department visits per 1,000 cine; now it’s two doses,” he said. practice,” said Dr. Joseph W. St. Geme III children during the 2002-2003 season and Rotavirus Vaccine Also, routine vaccination with two dos- of Duke University, Durham, N.C., who, 95 clinic visits and 27 emergency depart- Two phase III trials of live, attenuated ro- es of a live mumps virus vaccine is rec- along with Dr. Janet Englund of the Uni- ment visits per 1,000 children during the tavirus vaccines for severe rotavirus gas- ommended for health care workers born versity of Washington, Seattle, presented 2003-2004 season. troenteritis were among this year’s most during or after 1957 without other evi- the past year’s top findings in pediatric in- Of particular interest, Dr. Englund not- important pediatric infectious disease stud- dence of immunity. One dose is recom- fectious disease. ed, was the fact that only 28% of the in- ies, said Dr. Englund. The vaccines—an mended for health care workers born be- patient population and 17% of the outpa- oral pentavalent human-bovine reassor- fore 1957 without other evidence of Human Bocavirus tient population with laboratory- tant rotavirus vaccine (RotaTeq) and a immunity. In outbreak settings, a second “One of the major problems in pediatrics confirmed influenza two-dose oral mono- dose of a live mumps virus vaccine should continues to be respiratory tract infec- received a discharge ‘One of the major problems valent human ro- be considered for children ages 1-4 years tions,” said Dr. St. Geme. Along these diagnosis of influen- tavirus vaccine (Ro- and adults at low risk, within a 28-day in- lines, Dr. John C. Arnold and his colleagues za by the treating in pediatrics continues to tarix)—were terval. For health care workers born be- assessed the prevalence and clinical spec- physician, “despite be respiratory tract independently stud- fore 1957 without other evidence of im- trum of the recently identified human bo- the availability of on- ied in large, multicen- munity, two doses should be seriously cavirus (HBoV) among nearly 1,500 chil- site testing.” Of even infections,’ including ter trials that included considered (MMWR 2006;55:1-2). dren aged 0-18 years who were treated for more concern, she the recently discovered more than 60,000 respiratory tract infection over a 20-month added, “is that fewer children each (N. Live Attenuated Influenza Virus Vaccine period at the Children’s Hospital, San than half of the chil- human bocavirus. Engl. J. Med. 2006; The theoretical potential of secondary Diego (Clin. Infect. Dis. 2006;43:283-8). dren in the ICU set- 354:11-22; N. Engl. J. transmission of influenza has been a con- The investigators screened by poly- ting had a diagnosis of influenza made Med. 2006;354:23-33). Compared with cern related to the use of the live attenu- merase chain reaction 1,474 nasal scraping during their hospitalization.” placebo, both vaccines demonstrated sig- ated influenza virus vaccine (FluMist). In specimens that had been collected and The take-home message is that “in- nificant efficacy in reducing severe gas- previous studies, shedding of vaccine frozen, and they found HBoV DNA in fluenza is underrecognized and underap- troenteritis and hospital admissions asso- viruses has not been associated with viral 5.6% of the specimens. The researchers preciated, even by pediatricians,” noted ciated with rotavirus, and both reduced all transmission to close contacts. noted that the peak infection rate was be- Dr. Englund. Increasing awareness and diarrhea-associated hospital admissions by In an effort to estimate the probability tween March and May in both 2004 and adopting and promoting broader univer- approximately half, which suggested that of transmission in a “worst-case scenario,” 2005 and that 63% of the patients were sal vaccination strategies “has the poten- a high proportion of the diarrhea-associ- Dr. Timo Vesikari of the University of younger than 12 months. tial to decrease the outpatient burden.” ated admissions in the study areas were Tampere (Finland) and colleagues con- Evidence of underlying disease, including linked to rotavirus, noted Dr. Englund. ducted a trial in a day care setting, said Dr. asthma, bronchopulmonary dysplasia, neu- Infant Botulism Both vaccines also had good safety pro- Englund. “This study was designed by the romuscular disease, and trisomy 21, was Infant botulism, caused by ingestion of files. In particular, there was no evidence authors to maximize opportunity for present in roughly one-third of the patients. Clostridium botulinum bacteria, which then of an increased intussusception risk fol- transmission by including young children The most common symptoms were germinate and produce toxins in a baby’s lowing vaccine administration as had been without immunity and without prior ex- cough (present in 85% of cases), rhinor- large intestine, is the most common form reported with the first-generation ro- posure or minimum exposure to influen- rhea, and fever. Clinical evidence of low- of human botulism in the United States; tavirus vaccine (RotaShield) that was on za in a close-contact setting,” she said. er respiratory tract HBoV infection was 80-110 cases occur per year. A rare but se- the market in the late 1990s. The study included 197 children be- present in 62% of the children, and near- rious and potentially fatal condition, infant Perhaps the most important outcome of tween 9-36 months of age from 52 differ- ly half of the patients had hypoxemia. Ap- botulism typically requires hospitalization both of these studies “is that they set the ent day care center rooms who were ran- proximately 19% of HBoV-infected pa- for 4-6 weeks and often requires mechan- standard now for what all vaccine manu- domized 1:1 to receive the vaccine or tients had paroxysmal cough, which led to ical ventilation. Although adults with bot- facturers are going to do or have the abil- placebo. Nasal swabs were taken at regu- further testing for pertussis. ulism poisoning can be treated effectively ity to do in the future,” said Dr. Englund. lar intervals to determine postvaccination Based on the findings, “it’s clear that with an equine-derived botulism antitox- As a result of the positive data coming viral shedding, genotype and phenotype of more widely available diagnostic testing in, the treatment is not used in infants be- out of these large trials, the Advisory shed viruses, and the probability of sec- for human bocavirus will be a priority in cause of the risk of serious side effects, Committee on Immunization Practices ondary transmission of the vaccine in- terms of establishing a better under- such as anaphylaxis and serum sickness. (ACIP) issued a recommendation in the fluenza strains (Pediatr. Infect. Dis. J. 2006; standing of the epidemiology and clinical For this reason, the development and summer of 2006 that all U.S. infants be im- 25:590-5). manifestations,” said Dr. St. Geme. successful testing in infants of a human- munized against rotavirus with three dos- Of the 98 children who received the vac- derived botulism antitoxin called BIG-IV es of the already Food and Drug Admin- cine, 80% shed at least one vaccine in- Influenza in Young Children (Human Botulism Immune Globulin-In- istration–approved RotaTeq vaccine, fluenza strain. All of the vaccine virus iso- “In contrast to a new virus that we can’t travenous) by Dr. Stephen S. Arnon of the administered at 2, 4, and 6 months. lates retained their cold adaptation and diagnose, influenza is an old virus that we California Department of Health Services Because the rotavirus burden is highest temperature sensitivity characteristics. can diagnose,” said Dr. Englund while and his colleagues in the Infant Botulism in underdeveloped countries, “efforts There was one confirmed transmission of presenting a paper on the burden of in- Treatment and Prevention Program was should be made to conduct clinical trials a vaccine strain to a placebo recipient, but fluenza in young children by Dr. Cather- “tremendously important,” according to in these regions and to determine ways to the child did not exhibit any signs or symp- ine Poehling of Vanderbilt University, Dr. St. Geme. In the first of two studies in- pay for the vaccine, which is relatively ex- toms of clinically significant influenza. Nashville, Tenn., and her colleagues at the cluded in the published paper, 122 infants pensive,” Dr. Englund noted. “Such efforts The probability of secondary transmission Center for Disease Control and Preven- (age range, 21-313 days) with laboratory- are worthwhile considering the vaccine of influenza from one vaccinated child tion’s New Vaccine Surveillance Network confirmed infant botulism were random- has the potential to prevent 5% of child- was calculated to be approximately 0.58%. (N. Engl. J. Med. 2006;355:31-40). ized to receive BIG-IV or placebo within hood deaths worldwide.” “This study showed that, even in the The investigators used population-based 3 days of hospital admission. Infants who worst conditions and despite the high rate surveillance to assess the disease burden of received BIG-IV had significantly shorter Mumps Vaccination Update of viral shedding following vaccination, influenza among children younger than 5 hospital stays, compared with the placebo Mumps also made its way into the infec- there is a low potential for secondary trans- years who were seeking medical care for group (mean 5.7 vs. 2.6 weeks), and short- tious disease news this year. In response to mission of influenza,” said Dr. Englund. ■