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Biomedical subjects

J V Bennett

Publications and source records attributed to J V Bennett.

At least 19 recordsLinked to original sources
PubMed2000

Response to different measles vaccine strains given by aerosol and subcutaneous routes to schoolchildren: a randomised trial.

BACKGROUND: More than one dose of measles vaccine is necessary for the sustained control of measles. The aerosol route is thought to be more immunogenic for booster doses than traditional subcutaneous injections, so we did a randomised comparative trial of aerosol and subcutaneous measles vaccines in South African schoolchildren. METHODS: 4327 schoolchildren (aged 5-14 years), assigned by block randomisation of classrooms, received standard titre doses of either Schwarz or Edmonston-Zagreb measles vaccines subcutaneously or by aerosol. Blood samples for antibody assay were collected before vaccination, at 1 month, and 1 year after vaccination. The main endpoints (antibody titres at 1 month and 1 year) were compared between groups. FINDINGS: 992 children had antibody titre data available for all timepoints. 14 (3.6%) of 385 children who received Edmonston-Zagreb vaccine by aerosol were seronegative 1 year after vaccination, compared with 28 (8.6%) of 326 children who received Edmonston-Zagreb subcutaneous vaccine and 39 (13.9%) of 281 children who received Schwarz subcutaneous vaccine. At 1 month, 326 (84.7%) children who received aerosol Edmonston-Zagreb vaccine had seroconverted, compared with 257 (78.8%) who received subcutaneous Edmonston-Zagreb vaccine and 176 (62.6%) who received subcutaneous Schwarz vaccine. At 1 month, only 116 (22.7%) of 511 children in the Schwarz aerosol group had seroconverted; this aerosol vaccine had no detectable potency after 2 min of nebulisation. There were no serious side-effects: about 5% of children in each group had a rash within 2 weeks of vaccination. INTERPRETATION: An aerosol vaccination method that uses currently available devices and a suitably stable vaccine is effective and acceptable. This form of delivery is adaptable to mass campaigns, avoids the risks associated with injections, and could help measles eradication.

Administration, Inhalation↗
PubMed1999

Dry powder inhalation as a potential delivery method for vaccines.

Measles vaccine is administered to millions of children annually via a percutaneous injection. There are, however, compelling reasons to search for alternative routes of administration, especially in mass vaccination campaigns. Two key factors are (1) decreased stability of the vaccine upon reconstitution and, (2) the potential risks of contamination associated with needles. Dura has developed a unique inhaler that can deliver a powder dose via the pulmonary route for local or systemic action. The breath-actuated Spiros inhaler uses electromechanical energy to aerosolize and deliver a consistent dose over a wide range of inspiratory flow rates. To achieve alveolar (deep lung) deposition for subsequent systemic absorption, dry-powder vaccine is size reduced to a mass median diameter between 1 and 5 microns. Small vaccine particles are blended with an inert carrier to improve dispersion. Measles vaccine formulated as a powder blend may be more thermostable than existing reconstituted formulations. The Spiros technology is available in three powder storage platforms. Two of these formats are designed specifically for moisture and/or light sensitive compounds and may be particularly suitable for delivery of measles vaccines in mass campaigns because their design (1) eliminates the need for powder reconstitution, and (2) reduces the risk of contamination.

Administration, Inhalation↗
PubMed1998

Topical antimicrobials applied to the umbilical cord stump: a new intervention against neonatal tetanus.

BACKGROUND: Previous case-control studies of neonatal tetanus (NNT), a leading cause of infant mortality in developing countries, have suggested that antimicrobials applied after delivery to the umbilical cord stump may protect against this disease. However, assessment of their protective effect has been limited by the low prevalence of antimicrobial use in developing countries. METHODS: We conducted a population-based, matched, case-control study to assess the use of antimicrobials and other factors potentially related to NNT in rural parts of Bangladesh. We studied 359 cases (infants who were normal at birth but who died between the 3rd and 30th day of life after an illness characterized by signs of NNT), each matched to three living controls for gender, residence, and date of birth. RESULTS: In univariate analyses, the application of either antibiotics or disinfectants at delivery, and the continuous or any application of disinfectants were protective against NNT. The application of antibiotics at delivery (odds ratio [OR] = 0.21, P = 0.019), hand washing by the delivery attendant (OR = 0.64, P = 0.005), and prior maternal immunization with tetanus toxoid (OR = 0.50, P < 0.001) remained protective in conditional logistic-regression analyses. Application of animal dung to the umbilical stump (OR = 2.31, P = 0.047) was hazardous. CONCLUSIONS: Effective and inexpensive topical antimicrobials provide a new prevention opportunity that could be used by traditional birth attendants and mothers to provide additional benefits to NNT control programmes based on maternal immunization with tetanus toxoid. Promotion of hygienic delivery and cord-care practices and increasing tetanus toxoid coverage remain cornerstones for the prevention of NNT deaths.

Administration, Topical↗
PubMed1997

Alternative routes of measles immunization: a review.

Measles is one of the major causes of childhood mortality in developing countries, despite current prevention of over 2 million child deaths each year by measles vaccination programmes. New strategies, such as mass campaigns, and possibly new preparations of measles vaccines, may facilitate further progress in controlling the disease and improving the prospects for its ultimate eradication. To evaluate the potential for non-percutaneous routes of vaccine administration to improve control, we reviewed studies of serological responses to measles vaccine after intradermal, conjunctival, oral, aerosol and intranasal administration. The response to intradermal vaccination exceeded percutaneous results in only one of eight instances in five studies where such comparisons could be made, often producing substantially lower seroresponses. Further, intradermal administration using a needle and syringe is more difficult than subcutaneous vaccination. After oral administration of vaccine, less than 50% of children seroconverted in three small studies. Intranasal administration has not yet been studied extensively, but it may be susceptible to interference by upper respiratory infections. Seroconversion after conjunctival administration was very variable, and this route was difficult practically in young children. In infants below 9 months of age, aerosol administration of vaccine resulted in 80% or better seroresponse in seven of nine trials, with the Edmonston-Zagreb strain in standard titre doses consistently producing better results than the Schwarz strain. However, seroresponses after subcutaneous administration clearly exceeded those from aerosols of the same vaccine in four of six comparisons. Several trials noted practical difficulties in aerosol administration in young infants. In contrast, older seronegative children generally responded well to aerosol administration of vaccine (above 90% and often 100% seroresponse), regardless of vaccine strain and often with surprisingly low estimated retained doses. In each of three studies where it was possible to compare the same vaccines given percutaneously and by aerosol to seropositive children, better seroresponses followed aerosols. In older children, aerosols of the Edmonston-Zagreb strain also rather consistently provided better seroresponses than aerosols of the Schwarz strain, with the most notable differences in seropositive children. Thus, with the possible exception of very young infants, the aerosol route is promising and offers several theoretical and practical advantages as well. Further randomized trials should be conducted to evaluate comparative responses to aerosolized, intranasal, and subcutaneous vaccine, especially in those age ranges targeted for mass campaigns (most commonly 9 months to 15 years). The development of improved technology for aerosol delivery of measles vaccine would greatly advance the potential for wide scale use of this route, especially in mass campaigns in low income countries.

Adolescent↗
PubMed1992

Neonatal tetanus in rural Bangladesh: risk factors and toxoid efficacy.

OBJECTIVES: Tetanus continues to be a leading cause of neonatal death in Bangladesh as in other developing countries, yet little is known about risk factors or the efficacy of tetanus toxoid in this setting. METHODS: In May 1990, mothers of 6148 infants born alive between March 15, 1989, and March 14, 1990, in 30 rural unions of Rajshahi Division in Bangladesh were interviewed. Three surviving controls for each neonatal tetanus death were matched for sex, residence, and date of birth. RESULTS: Of 330 neonatal deaths, 112 met the case definition for tetanus. Risk was increased with a history of neonatal tetanus in a previous child, application of coconut oil to the vagina, and use of multiple ties on the umbilical cord. Risk was reduced by the birth attendant washing hands and using a cleaned cord-cutting tool. Risk was not reduced by a maternal history of two doses of tetanus toxoid (TT2), although estimated efficacy of TT2 was 45% (95% confidence interval = 16% to 64%). Subsequent to the survey, a reference laboratory reported to potency in three consecutive lots of tetanus vaccine from the production laboratory in Bangladesh. CONCLUSIONS: These findings identify high-risk mothers, stress the importance of washing hands and cleaning the cord-cutting tool, and demand improved quality control of tetanus vaccine production.

Administration, Intravaginal↗
PubMed1991

Child survival and perinatal infections with human immunodeficiency virus.

A mathematical model was developed to assess the effect of various assumed prevalence rates of maternal human immunodeficiency virus (HIV) infection on perinatally acquired HIV infections and child survival. The model indicates that for children younger than 5 years, countries with low baseline mortality rates will experience greater relative increases in child mortality rates and larger proportions of HIV-caused deaths in children than countries with high mortality rates. It also suggests that perinatal HIV infection could become the most common cause of deaths in children in the developed world if maternal infection rates reach 2% to 3%. Rates of 25% to 30% would be needed to produce a similar effect in the developing world. Child survival gains in the last three decades in the developed world could be quickly erased at low levels of maternal HIV infection, but gains would not be completely offset in the developing world until more than 40% of mothers became infected with HIV. When basic demographic information and the maternal HIV infection rate are known, the model permits a direct assessment of infant and child mortality caused by HIV. It can also be used to estimate the prevalence of maternal HIV infection when values for all other variables are known.

Africa, Southern↗
PubMed1991

A reassessment of risk factors for neonatal tetanus.

A hospital-based case-control study was conducted to further examine the risk factors for neonatal tetanus (NNT) in the North-west Frontier Province of Pakistan. Three control infants were concurrently evaluated for each of 102 consecutively diagnosed NNT cases hospitalized over an 8-week period. Application of clarified butter (ghee) during the first few days of life was shown to be a significant risk factor, confirming our previously reported finding. However, the risk appeared to be limited to ghee made in the home from cow's milk. The tool used to cut the umbilical cord was again refuted to be a risk factor; application of topical antibiotics conferred significant protection. Multivariate analysis of the matched data showed that delivery by persons with academic training (physicians, nurses, and lady health visitors) was also protective. Mothers with a past history of NNT babies were shown to have a significantly increased risk, and accounted for more than one-third of all cases in the present study. The findings suggest possible ways to augment the effectiveness of NNT elimination programmes.

Butter↗
PubMed1989

Ghee applications to the umbilical cord: a risk factor for neonatal tetanus.

A case-control study was done to elucidate risk factors for neonatal tetanus (NNT) in rural Pakistan; three controls were selected for each of the 69 cases. Factors commonly believed to be associated with NNT, such as the tool used to cut the umbilical cord and the method of preparing the tool, were not confirmed as risk factors. However, applying ghee to the wound stump was. New prevention opportunities deriving from the finding should be pursued aggressively while efforts to develop effective delivery systems to immunise mothers against tetanus continue, a task made difficult by sociocultural factors.

Butter↗
PubMed1985

How frequent are outbreaks of nosocomial infection in community hospitals?

A statistical algorithm was used to identify potentially important clusters among nosocomial infections reported each month by 7 community hospitals. Epidemiologic review and on-site investigations distinguished outbreaks of clinical disease from factitious clusters. In 1 year, 8 outbreaks were confirmed. They involved 82 patients--approximately 2% of patients with nosocomial infections and 0.09% of all discharges. One true outbreak occurred for every 12,000 discharges--at least 1 outbreak per year for the average community hospital. Five (63%) outbreaks were recognized independently by the hospitals' infection control personnel. Four (50%) resolved spontaneously; the hospitals' own control measures were necessary in 2; and 2 resolved only after an outside investigation. Organized surveillance appears necessary to detect some outbreaks, and control measures are needed to stop many. Since, however, outbreaks account for such a small proportion of nosocomial infections, infection control programs should be sufficiently staffed and managed so that most of the effort is directed toward the surveillance and control of endemic infection problems, but with adequate resources remaining to respond to outbreaks when they occur.

Cross Infection↗
PubMed1982

Risk factors for development of toxic shock syndrome. Association with a tampon brand.

In September 1980, we interviewed by telephone 50 patients with menstrually associated toxic shock syndrome (TSS) who had onset of illness in July or August 1980. These women were asked to provide information about the type of menstrual sanitary products used during the menstrual period associated with their illness. We also interviewed 150 age-matched control subjects, who were asked the same questions for the menstrual period that occurred in the same month as the illness of the matched case. All 50 cases, but only 125 of 150 controls, used tampons. Among women using tampons, cases were more likely to have used Rely brand tampons when compared with controls. No differences were found between cases and controls in the absorbency of tampon products used. No other factors studied through analysis of a follow-up questionnaire mailed five months after the first study were found to be significantly associated with the development of menstrually associated TSS.

Female↗
PubMed1981

Pontiac fever: isolation of the etiologic agent (Legionella pneumophilia) and demonstration of its mode of transmission.

Pontiac fever, a unique epidemiologic form of legionellosis, is characterized by a short (one- to two-day) incubation period and a self-limited grippe-like illness without pneumonia. In 1968, the first documented outbreak of this syndrome affected persons who had entered a health department building in Pontiac, Michigan. Epidemiologic analyses clearly implicated as airborne agent and suggested that evaporative condenser water aerosols being disseminated by a defective air conditioning system played a key role in the outbreak. Guinea pigs that were exposed in the building and to laboratory aerosols of evaporative condenser water developed bronchopneumonia. Legionella pneumophilia (serogroup 1) was isolated from the exposed guinea pigs' lungs. Paired acute and convalescent serum specimens from 37 patients were tested by the indirect fluorescent antibody technique using L. pneumophila serogroup 1 antigen, and 31 (84%) had rises in titer from less than 32 to greater than or equal to 64.

Air Conditioning↗