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Biomedical subjects

D A Clements

Publications and source records attributed to D A Clements.

At least 19 recordsLinked to original sources
PubMed2001

Partial uptake of varicella vaccine and the epidemiological effect on varicella disease in 11 day-care centers in North Carolina.

BACKGROUND: The increasing use of varicella vaccine in children attending day care has rapidly decreased the incidence of wild-type varicella disease. The herd immunity noted is significant and will have an effect on the epidemiology of natural varicella. OBJECTIVE: To monitor the change in varicella incidence in day-care attendees after the licensure of varicella vaccine. DESIGN: A prospective observational cohort study design. SETTING: Eleven private day-care centers and preschools in North Carolina participated in the study from January 1, 1995, through December 31, 1999. PARTICIPANTS: All children in the 11 centers were eligible for participation. Some participated more actively, supplying information on a regular basis. Others participated passively. Day-care personnel provided information about all cases of varicella. INTERVENTIONS: None. MAIN OUTCOME VARIABLES: The change in the incidence of varicella disease was documented as the use of varicella vaccine increased. RESULTS: Varicella vaccine coverage increased substantially from 4.4% in 1995 to 63.1% in December 1999. The vaccination rate accelerated dramatically in 1996 and 1997, leveled off in 1998, and rose again in 1999. Cumulative varicella incidence decreased from 16.74 cases per 1000 person-months in July 1996 to 1.53 cases per 1000 person-months in December 1999 in unvaccinated children. CONCLUSIONS: The varicella vaccination rate continued to increase slowly in the day-care population after an initial rapid uptake. The decrease in varicella disease is greater than the increase in varicella vaccination. This herd effect is welcome and even apparent in the unvaccinated children younger than 1 year.

Age Distribution↗
PubMed1999

Concurrent administration of inactivated hepatitis A vaccine with immune globulin in healthy adults.

301 healthy adult volunteers were randomized to one of three treatment groups: inactivated hepatitis A vaccine alone; inactivated hepatitis A vaccine with immune globulin (Ig) concurrently; or Ig alone. The first two treatment groups received a second dose of hepatitis A vaccine at week 24. Anti-HAV was measured 4, 8, 12, 24 and 28 weeks after the primary immunization. When comparing subjects receiving inactivated hepatitis A vaccine alone to those receiving vaccine and Ig, the seropositivity rates were not significantly different at 4, 8, 12 and 28 weeks, but at week 24 the seropositivity rate was lower in the group receiving both vaccine and Ig compared to the group receiving vaccine alone (92.0% compared to 97.0%). At weeks 8, 12 and 24 the geometric mean titers (GMTs) were significantly lower for subjects receiving both vaccine and Ig. The GMTs were not significantly different after the second dose of vaccine. At all time points, the lower serum antibody concentrations observed in subjects receiving both inactivated hepatitis A vaccine and Ig were nevertheless substantially higher than the cutoff for assay seropositivity and much higher than after Ig alone; these differences are therefore clinically insignificant.

Adolescent↗
PubMed1999

Postlicensure study of varicella vaccine effectiveness in a day-care setting.

BACKGROUND: Varicella vaccine has been licensed for use in the United States since the spring of 1995. The acceptance of the vaccine and its effect on varicella incidence in children is important. AIM: To document the effectiveness of the varicella vaccine in children attending day care in 11 centers in North Carolina. METHODS: A dynamic cohort study design was used in 11 day-care centers in North Carolina. Multiple cross-sectional evaluations were performed and children were noted to be vaccinated or not and diseased or not. Vaccine effectiveness was estimated by comparing the varicella attack rate in the vaccinated with the varicella attack rate in the unvaccinated. Person time was used as the denominator for all calculations. RESULTS: During the study period February 1, 1996, to September 1, 1997, 134 cases of varicella occurred in the unvaccinated and 11 cases occurred in the vaccinated children. The attack rates in the vaccinated and unvaccinated were 2.49 and 14.66, respectively, for an overall vaccine effectiveness of 83% for mild/moderate disease. CONCLUSIONS: In the day-care setting varicella vaccine demonstrated benefit in preventing and modifying wild-type varicella disease.

Chickenpox↗
PubMed1996

Modified varicella-like syndrome.

After incidental exposure to natural varicella, up to 18% of vaccinees reported a breakthrough infection known as modified varicella-like syndrome (MVLS) over up to 10 years of postvaccination follow-up, compared with natural varicella occurring in similarly aged unvaccinated children at the rate of 9% per year. Children with MVLS are frequently asymptomatic, and their disease is characterized by having fewer lesions, less fever, and lasting fewer days than natural varicella. When a case of MVLS occurs there are few secondary cases, suggesting that it is infrequently transmitted. Sequelae such as secondary bacterial infection, cerebellar ataxia, encephalitis, and pneumonia occur infrequently.

Chickenpox↗
PubMed1995

Influenza A vaccine decreases the incidence of otitis media in 6- to 30-month-old children in day care.

OBJECTIVE: To determine if the use of influenza vaccine in children in day care decreases the incidence of otitis media during the influenza season. DESIGN: Prospective cohort study. SETTING: Eight day-care centers in North Carolina. PARTICIPANTS: One hundred eighty-six children aged 6 to 30 months. INTERVENTION: Half the participants received trivalent subvirion influenza virus vaccine. MEASUREMENTS: Acute otitis media (AOM) and serous otitis media (SOM) were assessed biweekly from mid-November 1993 to mid-March 1994 by visual and tympanometric examinations performed by "blinded" observers. The winter season was divided into three periods-before, during, and after influenza season--and the number of children with AOM or SOM during each period was determined. Unadjusted and adjusted odds ratios (ORs) were computed, while controlling for race and sex using logistic regression methods. RESULTS: Influenza vaccine was protective against AOM (OR = 0.69, 95% CI, 0.49-0.98) during the influenza season. Although there may have been some protection against SOM (OR = 0.75, 95% CI, 0.54-1.02) statistical significance was not achieved. Myringotomy tubes were also significantly protective against AOM and SOM during all three time periods, with ORs between 0.34 and 0.52, but the greatest protection was seen during the influenza period. CONCLUSIONS: Influenza vaccination of 6- to 30-month-old children in day care was associated with a decreased incidence of otitis media during the influenza season. Myringotomy tubes protected against AOM and SOM during all 16 weeks monitored.

Acute Disease↗
PubMed1995

Maternal acceptance of voluntary human immunodeficiency virus antibody testing during the newborn period with the Guthrie card.

In order to provide the opportunity for women delivering newborns to have human immunodeficiency virus (HIV) testing we piloted a hospital-based voluntary HIV testing program during the newborn period using the Guthrie card. During the study period 789 women were offered newborn HIV antibody testing. Test acceptance during the newborn period (61.0%) was comparable to that reported for the prenatal period (60.6%). Overall 77.4% of women were tested in the newborn period or reported being tested in the prenatal period. Prenatal test acceptance best predicted newborn HIV test acceptance (odds ratio, 3.37; 95% confidence interval, 2.40 to 4.74). When compared to HIV testing during the newborn period prenatal HIV testing is preferable because it enables the recognition of HIV infection early during pregnancy and allows the mother the option to elect zidovudine therapy and potentially prevent infection in her newborn. However, when prenatal HIV testing is not routinely made available or cannot be assured, women should be offered the opportunity to be tested during the newborn period.

AIDS Serodiagnosis↗
PubMed1995

Over five-year follow-up of Oka/Merck varicella vaccine recipients in 465 infants and adolescents.

A total of 465 healthy infants and adolescents ages 12 months to 17 years without a known history of varicella or recent exposure to varicella-zoster virus VZV were immunized with live attenuated Oka/Merck varicella vaccine from November, 1984, through April, 1989. The vaccine administered was from 1 of 7 production lots containing from 950 to 3265 plaque-forming units and was well-tolerated with few side effects. The seroconversion rate for seronegative subjects was 94.6% (403 of 426). This varied by lot from 85% (950 plaque-forming units) to 100% (3010 and 3265 plaque-forming units). Breakthrough disease after exposure to varicella in seroconverters during 5 to 10 years of follow-up was 18.6% (75 of 403). The breakthrough disease was characterized by a maculopapular rash with a median of 35 lesions, most of which were macules. Breakthrough disease lasted a median of 5 days and the median temperature was 99 degrees F; 65.3% (49 of 75) of subjects were afebrile and 2.7% (2 of 75) of subjects had temperatures of > 102.9 degrees F. Varicella vaccine provides excellent (94.6%) seroconversion, and most children who developed breakthrough disease (18.6%) experienced a modified, milder form of illness than has been observed with natural varicella in unvaccinated subjects.

Adolescent↗
PubMed1995

Clinical manifestations and outcome of Haemophilus influenzae type b disease.

OBJECTIVE: To document clinical manifestations, laboratory findings and outcome of childhood Haemophilus influenzae type b (Hib) infections. METHODOLOGY: Medical records of 235 children with Hib disease admitted to hospital during a 2 year period were reviewed; additional information was obtained by questionnaire and follow up 6 weeks after discharge. RESULTS: Three-quarters of patients presented with either meningitis or epiglottitis. Children with epiglottitis were older, had shorter illnesses and were less likely to have had antibiotics before admission than those with meningitis; 38% of the latter had been given some antibiotic therapy, with no apparent effect on the outcome. Fever persisted for 7 days or more in 23% of patients with meningitis. Death from meningitis occurred in 3.8% of patients and was due to fulminating disease. CONCLUSIONS: These data will assist in recognition and appropriate management of Hib disease as the clinical manifestations become less familiar following the introduction of immunization. Specific laboratory diagnosis is required for accurate surveillance, which should be maintained in order to ensure high immunization rates.

Adolescent↗
PubMed1995

A case-control study examining risk factors for invasive Haemophilus influenzae type b disease in Victoria, Australia 1988-90.

OBJECTIVE: To determine whether day-care attendance was a risk factor for Haemophilus influenzae type b (Hib) disease, particularly for epiglottitis. METHODOLOGY: A case-control analysis of risk factors for invasive Hib disease was performed in Victoria, Australia between February 1988 and February 1990 prior to the introduction of immunization for Hib. A total of 210 cases and 367 day surgery hospital controls were enrolled prospectively. Data were collected by questionnaire at the time of admission. RESULTS: Logistic regression analysis showed that risk factors for meningitis were day-care attendance, household crowding and recent illness in a sibling. Risk factors for epiglottitis were day-care attendance and mother's birthplace in Australia or New Zealand. CONCLUSIONS: This study confirms that day-care attendance is a risk factor for Hib epiglottitis as well as meningitis. In addition, the mother's birthplace in Australia or New Zealand is a risk factor for epiglottitis in these data. The reason for this latter observation is unclear.

Case-Control Studies↗