JOURNAL CLUB

JOURNAL CLUB

Giving rotavirus vaccine with other vaccines

A new study shows thatin healthy infants an oral tetravalent rotavirusvaccine (RV­TV) can be safely coadministered with a combined diphtheria-tetanus-pertussis-Haemophilusinfluenzaetype B vaccine (DTP/Hib) and oral poliovirus vaccine (OPV) withoutinterfering with the immune response to any of the component antigens. TheFood and Drug Administration recently approved a rotavirus vaccine, whichis included in the Recommended Childhood Immunization Schedule for 1999.

Investigators assigned 267 infants from 2 to 3 months of age to receivethree doses of either placebo or RV­TV concurrently with DTP/ Hib andOPV at 2, 4, and 6 months of age. They assessed immune response by measuringserum antibody titers to each component of DTP/Hib and OPV at three to sixweeks after the third dose. The infants also were followed for adverse events.No statistically significant difference was seen between the RV­TV andplacebo groups in the percentage of infants who attained protective antibodytiters or in the distribution of these titers against diphtheria toxoid,tetanus toxoid, H influenzae type b, Bordetella pertussis, and the threeserotypes of poliovirus. Postvaccination reactions also were similar inRV­TV and placebo recipients (Markwick AJ et al: Pediatr Infect DisJ 1998; 17:913).

Commentary: This vaccine is reportedto be 48% to 68% effectiveagainst all rotaviral disease and 70% to 91% effective against severe disease.It may significantly reduce the 50,000 annual rotavirus-related hospitalizationsin the United States. And if the cost of the vaccine falls, it may havea much larger impact on both morbidity and mortality in developing countries.

Parents "clueless" about risky behaviors

Using a confidential survey, investigators asked parents whether theirchildren engaged in certain risky behaviors and compared their responseswith those of the youngsters themselves. They queried 140 poor and middle-classseventh- and eighth-grade students (45% girls and 55% boys) and their parentsabout use of tobacco, alcohol, drugs, and diet pills; attempts to lose weightthrough diet and exercise; sexual intercourse; failure to use seat beltsand bike helmets; and suicide attempts.

Students and parents agreed about the prevalence of behaviors that parentscan observeeasily, such as use of seat belts and bicycle helmets, use ofdiet pills, and attempts to lose weight. There were insignificant differencesin perception in certain other areas: dieting, exercising or vomiting tolose weight, and having physical fights in school. In a third group of riskbehaviors, however, differences in student and parent perceptions were obviousand large. Parents were unaware that their adolescent children carried weaponsto school, used LSD or cocaine, used marijuana, smoked tobacco, drank alcohol,or were sexually active. Parents sometimes didn't even know that their childhad attempted suicide. For five of the behaviors in this third group, studentsreported rates at least 10 times higher than those their parents reported(Young TL et al: Arch Pediatr Adolesc Med 1998;152:1137).

Commentary: I guess that I'm clueless, too. I admit to being surprisedthat 58% of seventh and eighth graders say they have had sexual intercourse,that 38% say they have used marijuana, and that 22% say they have attemptedsuicide.

Constipation and cow's milk intolerance

Italian researchers have shown that constipation can be a presentationof cow's milk intolerance. The investigators studied 65 children with chronicconstipation, ages 11 to 72 months, to measure the effect of restrictingconsumption of cow's milk. All the children had been unsuccessfully treatedwith laxatives and were being fed full-fat cow's milk, dairy products, orcommercial formulas derived from cow's milk. Each child was assigned toreceive either soy milk or cow's milk for two weeks. This was followed bya one-week period on an unrestricted diet, after which study subjects wereswitched to the other type of milk for another two weeks.

Constipation resolved in 44 of the 65 children (68%) while they consumedsoy milk. Constipation did not resolve in any of the children while theydrank cow's milk. A challenge with cow's milk after the two two-week studyperiods confirmed the association between cow's milk and constipation inall 44 children whose constipation resolved during the soy-milk diet. Childrenwith a response to soy milk were more likely than nonresponders to haveother manifestations of intolerance of cow's milk, such as bronchospasm,dermatitis, and rhinitis, and signs of hypersensitivity, such as specificIgE antibodies to cow's milk antigens. When the study began, respondersalso were more likely than nonresponders to have anal fissures and evidenceof inflammation of the rectal mucosa on biopsy (Iacono G et al: N Engl JMed 1988;339:1100).

Commentary: The authors note that they may be seeing a very selectedpopulation--all the children were constipated despite laxatives and werereferred to a pediatric gastroenterologist. In your population fewer than68% of constipated patients may respond to elimination of cow's milk. Restrictingmilk intake may be worth a try, however, especially if rhinitis, dermatitis,bronchospasm, or anal inflammation accompanies constipation.

Do anxiety levels rise with asthma severity?

The anxiety levels of children with asthma rise with the severity oftheir disease--but only according to their parents. In self-ratings, childrenwith severe asthma do not feel more anxiety than do children with mild ormoderate asthma or more than suggested by standardized norms. In fact, thisstudy, conducted in Colorado, Rhode Island, and Texas, showed no relationshipbetween asthma severity and the child's report of anxiety, even when thepossibility that the child might be repressing anxiety symptoms was takeninto account.

Investigators administered anxiety and adjustment questionnaires to 337asthmatic children from 7 to 19 years of age who attended two differentasthma camps or were hospitalized for their asthma at a tertiary referralcenter. Asthma severity was graded using guidelines from the National Institutesof Health. In addition, one parent of each child reported on the child'smedical history and behavior and the parents' own physical symptoms. Theseself-reported parental symptoms were a stronger predictor of parental perceptionof the child's anxiety than severity of the child's disease. Investigatorscommented that parents' ratings of the stress experienced by their severelyasthmatic children may reflect their own distress at having a child withsevere asthma (Wamboldt MZ et al: J Am Acad Child Adolesc Psychiatry 1998;37[9]:943).

Commentary: This study shows the resilience of children with chronicdisease and the impact of childhood chronic disease on the whole family.

The most severe asthmatics studied were nearly two years older than theother subjects (mean 12.4 years compared with 10.8 years). Maybe some ofthe parents' concerns and physical complaints related to their children'sadolescence rather than their asthma.

Maternal youth is chief risk for infant homicide

Investigators identified 2,776 homicides in the US between 1983 and 1991in which the victims were under 1 year of age, using linked birth and deathcertificates, and determined risk factors for the deaths. Half the homicidesoccurred by the infant's fourth month of life. The analysis showed thatchildbearing at an early age is a strong risk factor for infant homicide,particularly if the mother has given birth previously and has had no prenatalcare. Childbearing before the age of 17 years accounted for 2.4% of birthsand 6.8% of the deaths in the study. In almost 17% of the homicides, thevictims were among the 5.1% of infants whose mothers were younger than 17or had two or more children by the age of 19. Other less significant maternalrisk factors for infant homicide are 11 years or fewer of education, singlemarital status, black or American Indian race, and gestation of less than28 weeks (Overpeck MD et al: N Engl J Med 1998;339:1211).

Commentary: These researchers express the hope that their resultsmay allow for targeted prevention of homicide in infants at highest risk.They estimate that an infant born to a mother younger than 17 is 10 timesmore likely to be the object of a homicide in the first year of life thana child born to a womanwho is at least 25 years old. JB Hardy and colleaguesreported that birth to a teenage mother is also an independent risk factorfor failure to graduate from high school, dependence on public assistanceas an adult, and having a child before the age of 20 (Pediatrics 1997;100:802).It seems like the most effective prevention would be to discourage earlypregnancy.

Early sexual intercourse related to peer norms

Investigators conducted a prospective cohort study in 14 elementary andmiddle schools in an urban district to determine which peer norms influencesexual initiation in young adolescents. The 1,389 sixth-grade students (meanage 11.7 years) in the study completed a questionnaire at the beginningof the school year about their intention to have sexual intercourse forthe first time in the upcoming year, sexual and non-sexual risk behaviorsin which they had engaged, perceptions of peers' risk behaviors, and whatthey thought their peers believed was a reasonable time to have intercoursefor the first time. The students answered the questionnaire again at theend of the school year.

Of students entering the sixth grade, 30% reported already having hadsexual intercourse (initiated group),and were excluded from further analysis.About 63% of students had not had sexual intercourse at the beginning ofthe sixth grade and continued to be abstinent during that school year (nevergroup). Investigators compared this 63% with the 5% of students who reportedno previous sexual activity on the first survey and first had sexual intercourseduring the sixth grade (initiated group).

Those in the initiated group were significantly more likely than studentsin the never group to believe that "most friends" were sexuallyexperienced and that sexually experienced 12-year-old boys gained respect.Conversely, students in the never group were more likely than those in theinitiated group to believe that sexual experience in a 12-year-old boy carriesa negative stigma. The initiated group thought the usual age for initiatingsexual intercourse was 15.4 years; the never group thought this age was16.2 years. Both groups had the same beliefs about the social gains andstigma sexual experience confers on a 12-year-old girl.

The study showed that the sixth graders who were most likely to havesexual intercourse for the first time in sixth grade were those who hadresolved to do so and that this resolve was likely to arise from the beliefthat most of their friends had already had intercourse (Kinsman SB et al:Pediatrics 1998;102:1185).

Commentary: The authors infer that the adolescents' perceptionthat most of their friends are sexually active encourages sexual initiation.If you believe these survey results, that perception is incorrect. Somehow,we need to convince children that despite what they hear in the locker roomand see on TV, it is not the norm to be sexually active in sixth grade.

Also of note

Parents unreliable historians on chronic medical problems. Questioningof family members or guardians before a routine visit at a cardiology, endocrinology,hematology/oncology, or neurology clinic in an urban tertiary hospital revealedthat caretakers of children with chronic medical problems are often unableto relay accurate information on their child's essential medical needs.Of the 49 caretakers interviewed, more than half did not know their child'sspecific diagnosis. Of the caretakers who could not name a specific diagnosis,half could give a lay diagnosis, while the other half could identify onlythe organ system involved or that there was a problem. For children on medications,29% of caretakers could not provide an accurate list of what was prescribed.Twenty-five percent of caretakers did not know the name of the subspecialistcaring for the child or the phone number of the subspecialty clinic. Nochild wore medical identification jewelry (Carraccio CL et al: Pediatrics1998;102 [2]:367).

Doctors' handwriting--an argument for an electronic medical record. Ascientific study supports what everyone has always suspected: Doctors' handwritingis unusually illegible. Investigators used computer software for opticalcharacter recognition to compare the handwriting of doctors, administrativestaff, and other health-care professionals in a health district in Wales.

Study participants were asked to complete a standard form and to writeas neatly as possible. The software scanned and translated the handwrittenreplies for computer analysis, highlighting any unrecognized charactersand generating an error score. Legibility of numbers was similar for allgroups. For letters, however, the doctors had a higher median error scorethan either of the other two groups individually or combined (Lyons R etal: BMJ 1998;317:863).

Commentaries by Michael G. Burke, MD