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At least 991 records · Page 55Linked to original sources
PubMed1995

Case-control study of HIV seroconversion in health-care workers after percutaneous exposure to HIV-infected blood--France, United Kingdom, and United States, January 1988-August 1994.

Health-care workers (HCWs) are potentially at risk for human immunodeficiency virus (HIV) infection through occupational exposures to blood. Although prospective studies indicate that the estimated risk for HIV infection after a percutaneous exposure to HIV-infected blood is approximately 0.3% (1,2), factors that influence this risk have not been determined. To assess potential risk factors, CDC, in collaboration with French and British public health authorities, conducted a retrospective case-control study using data reported to national surveillance systems in the United States, France, and the United Kingdom. This report describes the study and summarizes results that suggest that risk factors for HIV transmission include certain characteristics of the exposure and the source patient; in addition, postexposure use of zidovudine (ZDV) by HCWs was associated with a lower risk for HIV transmission.

Antiviral Agents↗
PubMed1996

[Value and limits of complementary investigations in cases of toxoplasmosis seroconversion during pregnancy. A case report and review of the literature].

We report a case of acute toxoplasmosis during the first trimester of pregnancy in which antenatal diagnosis was negative. Except for non-specific signs of liver failure, assessment by repeated ultrasound scans, testing of fetal blood for toxoplasmic specific antibodies and competitive PCR to isolate the parasite, had ruled out fetal infection. In spite of early treatment with spiramycin, and although the infant was assumed to be non-contaminated, severe hydrocephalus was noted at 3 and half months of life, arising soon after therapy had been stopped. This case focuses attention on the problem of the shortcomings of the diagnostic techniques currently used, and leads us to question our practical course of action. Several questions are thus raised: how reliable are indirect signs of fetal compromise, what is the real sensitivity of the PCR test and how useful are repeated amniocentesis and inoculation of the amniotic fluid to mice.

Acute Disease↗
PubMed1996

Influence of the specific T cell response on seroconversion after measles vaccination in autologous bone marrow transplant patients.

Six patients who were seronegative to measles after autologous bone marrow transplantation (ABMT) were vaccinated with a live attenuated measles vaccine. The specific T helper cell response was studied by measuring lymphocyte proliferation induced by measles antigen and B cell response by measles specific IgG by ELISA. Blood samples were drawn before, at 1-3 months, and at 1 year after vaccination. It was found that a pre-existing T cell response correlated with an impaired B cell response 1 year after vaccination (r = 0.83, P = 0.04), whereas no correlation was found between IgG titers before vaccination and IgG titer increase, or T cell response after vaccination. Furthermore, there was a transient negative correlation between the T cell response at 1-3 months after vaccination and the T cell response before vaccination (r = -0.90, P = 0.04) that became positive at 1 year after vaccination (r = 0.90, P = 0.02). In conclusion, in patients seronegative to measles who were revaccinated with measles vaccine after ABMT, a pre-existing T cell response correlated with an impaired B cell response, while pre-existing low-level IgG antibodies had no significant influence on the IgG titer rise. A sustained T cell response to measles antigen before vaccination may thus be one possible explanation for measles vaccine failure in ABMT patients.

Adolescent↗
PubMed1997

Differences by antigen in seroconversion: sensitivity, specificity and bias in the serological confirmation of pertussis.

Vaccine efficacy of the most efficacious acellular pertussis vaccines in the three recent placebo-controlled clinical trials, when estimated using the primary clinical case criterion, does not change substantially with the inclusion of serological confirmation in addition to culture confirmation. In the Italy trial, because of relatively high anti-PT antibody levels at the time of the acute-phase specimen in episodes of 21 or more days of paroxysmal cough, significant increases in antibody to PT are less likely to be seen in the acellular vaccine groups when evaluating children with bacterial isolation. However, the effect of this decreased sensitivity appears to be compensated by significant antibody increases in the FHA assay. When projecting a maximally sensitive criterion for serological assessment using the observed decreases in IgG antibody to PT over time following primary vaccination stratified by vaccine group, and comparing the expected antibody level with the observed level in the convalescent-phase specimen, the effect on estimated vaccine efficacy is minimal.

Antibodies, Bacterial↗