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Biomedical subjects

A Meheus

Publications and source records attributed to A Meheus.

At least 55 records · Page 3Linked to original sources
PubMed1995

Horizontal transmission of hepatitis B virus.

In 1991-92, a cross-sectional survey in Flanders (Belgium) for hepatitis B virus (HBV) markers among 277 relatives of institutionalised mentally handicapped persons to evaluate the prevalence of hepatitis B and the risk of infection showed that relatives of an HBV positive resident were 7.6 times more likely to be infected than relatives of an HBV seronegative mentally handicapped person. HBV infection among the family members could be attributed in 83% to exposure to an HBV positive resident. This study demonstrated the importance of horizontal transmission among relatives of institutionalised mentally handicapped people, even if family contact is reduced to weekend and holiday activities. We recommend that HBV vaccination policy should be expanded to include relatives of institutionalised mentally retarded people.

Belgium↗
PubMed1995

Risk of hepatitis B in adolescence and young adulthood.

In countries of low hepatitis B virus (HBV) endemicity, infection occurs mainly in adolescents and young adults (15-34 years old). The most important risk factors for infection are heterosexual activity, homosexual activity and intravenous drug use. In industrialized countries, therefore, HBV infection is classified among the major sexually transmitted infections, as more than 50% of infections are spread in this way. Transmission from mother to newborn and during infancy is of less importance, except in some countries of southern Europe and in some southern states of the USA. The highest concentrations of HBV are found in blood of infected individuals, but HBsAg is also present in semen and vaginal and cervical secretions, which forms the biological explanation for sexual transmission of the virus. In epidemiological studies, HBV is, in general, associated with indicators of sexual activity such as number of lifetime or recent sexual partners, years of sexual activity and a history or serological marker of other sexually transmitted infections. Providing immunity from infection before risk-taking behaviour is adopted should be the major control strategy for HBV infection. Just as for other sexually transmitted infections, this can be best achieved by universal vaccination of young adolescents or infants, or both groups.

Adolescent↗
PubMed1995

Mass antimicrobial treatment in pregnancy. A randomized, placebo-controlled trial in a population with high rates of sexually transmitted diseases.

Sexually transmitted diseases (STDs) are highly prevalent in pregnant women in many developing countries and have been associated with poor obstetric outcomes. Case detection and treatment of STDs in women is problematic and expensive, underscoring the need for other strategies. To explore the potential benefits of routine antimicrobial therapy on pregnancy outcome, we carried out a randomized, double-blind, clinical trial in one of the antenatal clinics in Nairobi, Kenya. Four hundred pregnant women between 28 and 32 weeks' gestation were given a single dose of 250 mg ceftriaxone intramuscularly or a placebo. There was a significant difference between ceftriaxone and placebo-treated women in infant birth weight (3,209 versus 3,056 g, P = .01). In addition, there was a trend toward lower rates of birth weight < 2,500 g (4.0% versus 9.2%, P = .08) and postpartum endometritis (3.8% versus 10.4%, P = .05) in the intervention than in the placebo group. Neisseria gonorrhoeae was isolated from the cervixes of postpartum women in 1.8% of the intervention group as compared to 4.2% of the control group. These data suggest a beneficial effect of antimicrobial prophylaxis on pregnancy outcome. Larger studies should be carried out to examine the public health impact of this intervention.

Adult↗
PubMed1994

Single dose inactivated hepatitis A vaccine: rationale and clinical assessment of the safety and immunogenicity.

In comparison with the classical immunisation schedules (0-1-6 or 0-1-12 months) for hepatitis A, a 0- and 12- or a 0- and 6-month schedule would have important advantages by reducing the number of injections and discomfort and increasing scheduling convenience and patient compliance. It would be convenient if a single dose with enough antigen could protect both rapidly and for at least 12 months, when the booster dose would be given. Several clinical trials have been carried out with an inactivated hepatitis A vaccine containing 1,440 EL.U. (1 ml), according to a 0-12 and a 0-6 vaccination schedule. This hepatitis A vaccine is safe and well tolerated. It offers a rapid seroresponse: 14 days after a single dose the seroconversion is 88% (95% C.I.: 84.6-90.9). The 0-12 schedule study showed good persistence of hepatitis A virus (HAV) antibodies with a seroconversion rate of almost 95% at month 12. Booster doses given at 6 or 12 months result in a substantial rise in antibody levels; according to these antibody titres, the 1,440 EL.U. vaccine can be expected to confer comparable duration of protection as the 720 EL.U. vaccine, i.e., 10-20 years. Preliminary data show that timing of the booster may not be critical for the antibody response. In conclusion, the 1,440 EL.U. hepatitis A vaccine is safe, offers rapid seroconversion, and is highly immunogenic. The persistence of HAV antibodies until month 12 allows a certain flexibility in the administration of the booster: month 6 or 12, and a 0-12 or 0-6 schedule can increase the vaccination compliance.

Adolescent↗
PubMed1994

Inactivated hepatitis A vaccine: reactogenicity, immunogenicity, and long-term antibody persistence.

This trial evaluated the reactogenicity, kinetics of antibody induction, and long-term immunogenicity of a 720 enzyme-linked immunosorbent assay units (EL.U.) antigen dose of an inactivated hepatitis A vaccine (Havrix, SmithKline Beecham Biologicals, Rixensart, Belgium). One hundred six healthy adult volunteers were enrolled to receive vaccine intramuscularly according to a 0, 1, and 6-month schedule. The vaccine was well tolerated. The most frequently reported local symptom was soreness, observed following 37.1% of all doses. Headache was the most frequently reported general symptom observed following 12.9% of documented vaccine doses. The administration of one vaccine dose induced seropositivity (anti-hepatitis A virus [HAV] > or = 20 mIU/ml) in 91% of all vaccinees 1 month later. The second vaccine dose resulted in seropositivity of the remaining vaccinees at month 2. All subjects remained seropositive for HAV antibodies at month 6, at which time the booster vaccine dose was given. At month 7, all vaccinees had anti-HAV titres > 200 mIU/ml. Serological results obtained at months 12, 18, 24, and 36 showed that antibodies against HAV induced by the vaccine booster dose persist for at least 30 months following its administration. All 49 subjects followed up until month 36 had antibody titres > or = 20 mIU/ml. The geometric mean titre (GMT) decreased by 60% from month 7 to month 12; between month 12 and 36, the GMT decreased by approximately 14% per period of 12 months. According to the vaccine-induced antibody kinetics and the magnitude of antibody level decrease over time, the predicted duration of antibody persistence is estimated to be at least 20 years.

Adolescent↗
PubMed1994

Anti-HBs kinetics after HBV vaccination in neonates.

BACKGROUND AND OBJECTIVES: We report the results of a study using a recombinant DNA HBV vaccine in newborns from an endemic area for HBV and compare the anti-HBs kinetics with observations in adults in order to make estimates about the need for booster vaccinations. STUDY DESIGN: One hundred and forty-eight neonates were vaccinated and followed for 62 months. Based on the presence or absence of hepatitis B surface antigen in the mother, cohorts of 'exposed' and of 'non-exposed' neonates were identified. RESULTS: A maximum concentration is normally observed after the booster vaccination followed by a rapid decline. According to Ambrosch et al. and Gesemann et al., titer calculations as a function of time, yielded 37 IU/1 and 47 IU/1 at month 60 respectively. The mean titer for the three groups of neonates investigated was at that time 74 IU/1. The prospective time intervals to arrive at an anti-HBs level of at least 10 IU/1 can be individually calculated from the individual titer after the booster vaccination. These calculated estimates show respectively: that 8.3% of the vaccinated neonates need a new booster vaccination within 14 months; that 26.7% will need a new booster within 50 months; and that only 65% need a new booster in 50 or more months. CONCLUSION: It can be concluded that anti-HBs kinetics in very young children and adults are comparable. The least expensive way of maintaining protection against HBV in neonates seems to be the determination of the individual titers after the first booster vaccination and calculation of the prospective time interval to arrive at a minimum titer of 10 IU/1 and the need for a new booster vaccination.

Journal Article↗
PubMed1992

Accuracy of two enzyme immunoassays and cell culture in the detection of Chlamydia trachomatis in low and high risk populations in Senegal.

Two enzyme immunoassays (EIAs), Chlamydiazyme (CZ; Abbott Laboratories) and Pathfinder (PF; Kallestadt), were compared with a cell culture technique in the detection of cervical Chlamydia trachomatis infection in 670 women in urban settings in Senegal (377 pregnant women and 293 prostitutes). Positive CZ and positive PF specimens were tested a second time using a monoclonal antibody blocking technique. True positive specimens were defined as those positive on culture or positive on EIA with confirmation of the result after blocking. Using this definition, the prevalence of genital chlamydial infection was 14.6% and 14.3% in pregnant women and prostitutes respectively. An important difference between the two populations was that the pregnant women were younger than the prostitutes, which might explain the fact that the prevalence of infection among the pregnant women was as high as that among the prostitutes, although the age-adjusted prevalence was higher among prostitutes than among pregnant women. The chlamydial detection rates of cell culture, CZ and PF were 62% (26/42), 69% (29/42) and 86% (36/42) respectively in prostitutes and 76% (42/55), 40% (22/55) and 53% (29/55) respectively in pregnant women. Agreement between the tests was 89%, 85% and 88% for culture/CZ, culture/PF and CZ/PF respectively. However, when data were adjusted for chance agreement, kappa coefficients were 0.40 for culture/CZ, 0.34 for culture/PF and 0.48 for CZ/PF. These results indicate that the accuracy of the EIAs and cell culture may vary greatly in different populations: both EIAs showed a distinctly higher detection rate than culture in prostitutes and a significantly lower detection rate in pregnant women.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Heat stability of a recombinant DNA hepatitis B vaccine.

The heat stability of a recombinant DNA hepatitis B vaccine was studied in healthy adult volunteers. When compared with vaccine stored at 4 degrees C, heating of the vaccine for 1 week at 45 degrees C or for 1 month at 37 degrees C did not alter the reactogenicity or the ability of the vaccine to elicit antibody titres considered to be protective. These results have significance in situations where the cold chain is broken, as can happen in countries where proper storage and transport facilities are not always available.

Adolescent↗
PubMed1992

The endemic treponematoses: not yet eradicated.

The endemic treponematoses which comprise yaws, endemic syphilis (bejel) and pinta constitute a group of potentially disabling and disfiguring infections which primarily afflict children in tropical and subtropical areas. Foci where these diseases are now endemic have a patchy distribution and are typically confined to underprivileged communities living in remote rural areas, with little or no access to health services and removed from the mainstream of socioeconomic development. A drastic decline in the prevalence of these infections was brought about by the implementation of mass treatment campaigns with penicillin under the technical guidance of WHO and with material support from UNICEF in the 1950s and 1960s. These worldwide campaigns against the endemic treponematoses halted disease transmission in many areas and held the promise of complete eradication if intensive surveillance could be continued for some time with the increasing involvement of the basic health services. National campaigns were so successful that relatively low priority was given to the preparation of the rural health services for this new task. The failure of many countries to integrate active control measures into the functions of the rural health services led to the gradual build-up and extension of treponemal reservoirs and the resurgence of foci of increased disease transmission particularly in communities where standards of hygiene and health care had remained low. In a number of former endemic foci only low-level transmission persisted; in a few areas disease prevalence increased dramatically to reach pre-campaign levels. The lack of technical and financial resources limited the success of renewed national control activities in the most affected areas. Today, with waning interest in these diseases confined to remote, and thus silent, population groups, and a decreasing ability of health staff to identify cases, data collected by countries need to be supplemented by information from other sources in order to arrive at a more valid assessment of the situation concerning the endemic treponematoses. Central and West Africa are most severely affected by the resurgence of the endemic treponematoses. In recent years a number of countries (e.g. Ghana, Côte d'Ivoire and Mali) have launched renewed control efforts, often combining yaws or endemic syphilis control with other public health programmes. In Central Africa itinerant pygmy groups are still highly affected by yaws and are an important source of infection for the sedentary population with which they come into contact. In Chad, Sudan and Ethiopia, there is some evidence of persistent foci of endemic treponematoses; the epidemiological situation in Southern Africa is not well established.(ABSTRACT TRUNCATED AT 400 WORDS)

Africa↗