Search PubMed⌕ Search

Biomedical subjects

S R Preblud

Publications and source records attributed to S R Preblud.

At least 55 records · Page 3Linked to original sources

Fetal risk associated with rubella vaccine: implications for vaccination of susceptible women.

The Centers for Disease Control has maintained a register of women who received rubella vaccine within three months before or three months after conception to follow prospectively the outcome of pregnancy and to quantitate the risks to the fetus from the vaccine virus. The data indicate that rubella vaccine can cross the placenta and rarely can infect the fetus. However, no abnormalities consistent with congenital rubella syndrome have been noted in 144 infants whose susceptible mothers received the RA 27/3 rubella vaccine, the only vaccine available in the United States since 1979. Although the observed risk of defects consistent with congenital rubella syndrome is zero, there is a statistical theoretic risk of a congenital rubella syndrome-like defect; the maximum theoretic risk is 2.6%. These findings indicate that vaccination of nonpregnant postpubertal women who lack either serologic proof of immunity or a written record of vaccination on or after the first birthday can be done safely and effectively. Whereas congenital rubella infection will disappear from the United States as vaccinated children enter the childbearing years, if these practices are followed elimination of congenital rubella infection will be hastened.

Disease Susceptibility↗

The opportunity and obligation to eliminate rubella from the United States.

The licensure of rubella vaccines in the United States in 1969 offered the opportunity to prevent the devastating consequences of congenital rubella infection, including miscarriages, therapeutic abortions, and congenital rubella syndrome (CRS), with its average lifetime cost of more than $220,000 per case. With the widespread use of vaccine, rubella transmission in the United States has been reduced to record low levels. Epidemics of rubella and CRS, previously reported every six to nine years, have not occurred, and since 1980, following decreases of rubella incidence rates in the postpubertal population, the endemic incidence rates of CRS have also begun to decrease. We have both the opportunity and the obligation to hasten elimination by (1) ensuring that susceptible females of childbearing age are vaccinated, (2) initiating and/or enforcing existing legislation requiring proof of rubella immunity for all children enrolled in schools, (3) intensifying surveillance for both acquired rubella and CRS, and (4) aggressively controlling rubella outbreaks.

Adolescent↗

Vancomycin dosage in pediatrics reconsidered.

Vancomycin hydrochloride levels were studied in 44 children (age range, 10 days to 10 years). These children received doses of vancomycin within current recommendations. Major variations in vancomycin levels were demonstrated in similar age groups and dosage regimens. For patients in the first month of life, second month of life, and older ages, respectively, 70%, 39%, and 30% of the peak determinations and 53%, 50%, and 23% of the trough determinations were greater than the desired level. Potentially toxic levels were found in eight patients.

Age Factors↗

Varicella vaccine trials in healthy children. A summary of comparative and follow-up studies.

Beginning in 1979, OKA and KMcC strains of varicella zoster virus (VZV) vaccine were administered to 369 healthy seronegative children in a sequence of ten comparative clinical trials. Postimmunization clinical reactivity was minimal with the OKA vaccines but was unacceptably high (32%) with the KMcC passage-40 vaccine. Ninety-three percent to 100% immunogenicity was noted by fluorescent antibody assay and in vitro lymphocyte proliferation to VZV antigens. Follow-up studies demonstrated persistence of antibody and in vitro lymphocyte proliferation responses and protection or modification of infection nine to 48 months after immunization. Only five episodes of mild varicella occurred in children in whom seroconversion had occurred. These episodes were noted after at least 281 known varicella exposures. Vaccine virus reactivation as zoster had not occurred in any child.

Adolescent↗

Bactericidal activities of chloramphenicol and eleven other antibiotics against Salmonella spp.

The bactericidal activity of chloramphenicol against 27 strains of Salmonella typhi and 33 strains of S. enteritidis was compared with those of 11 other antibiotics. The geometric mean bactericidal concentrations of chloramphenicol against susceptible strains (36.10 and 43.13 micrograms/ml for S. typhi and S. enteritidis, respectively) far exceeded those of the other 11 antibiotics, with cephalothin having the next highest values (2.67 and 8.66 micrograms/ml) and moxalactam (0.09 and 0.28 micrograms/ml), cefotaxime (0.08 and 0.28 micrograms/ml), ceftriaxone (0.07 and 0.16 micrograms/ml), norfloxacin (0.06 and 0.10 micrograms/ml), and aztreonam (0.05 and 0.20 micrograms/ml) having the lowest values. The results for imipenem (0.24 and 0.81 micrograms/ml) and ceftazidime (0.22 and 0.75 micrograms/ml) were lower than those noted for trimethoprim-sulfamethoxazole (1.20 and 5.56 micrograms/ml), cefamandole (0.62 and 3.29 micrograms/ml), and ampicillin (0.55 and 2.78 micrograms/ml). The MBC of chloramphenicol for some isolates decreased with increased incubation times such that the proportion of susceptible isolates killed by chloramphenicol at concentrations within achievable levels in blood increased from 10% after 24 h to 26% after 48 h of incubation. Although the MBC of the other 11 antibiotics for some isolates were also lowered by prolonged incubation, all 24-h values were within achievable levels in blood. The data indicate that chloramphenicol is not uniformly bacteriostatic against S. typhi and S. enteritidis. The in vivo significance of demonstrating delayed killing by chloramphenicol is, however, uncertain.

Anti-Bacterial Agents↗

Susceptibility of vaccine strains of varicella-zoster virus to antiviral compounds.

Using a plaque reduction assay, we determined the 50% effective doses of six antiviral compounds against low- and high-passage viruses of the KMcC and Oka strains of varicella-zoster virus vaccine. The potency, as indicated by the ranges of 50% effective doses (micrograms per milliliter) of the antiviral compounds, in decreasing order was as follows: (E)-5-(2-bromovinyl)-2'-deoxyuridine, 0.0007 to 0.0035; 1-(2'-flouro-2-deoxy-beta-D-arabinofuranosyl)-5-iodocytosine, 0.0063 to 0.0091; aphidicolin, 0.092 to 0.180; acyclovir, 0.79 to 1.81; vidarabine, 0.62 to 2.10; and phosphonoformic acid, 8.18 to 16.4. Susceptibility to the various antiviral compounds was independent of passage level or strain. These data, along with the available in vivo data, indicate that varicella-zoster virus vaccine infections requiring antiviral therapy most probably would be treated as effectively as would natural varicella infections.

Antiviral Agents↗

Rational strategy for rubella vaccination.

Current rubella vaccination programmes, devised when knowledge of vaccine characteristics was still incomplete, have not been fully successful in protecting those at maximum risk of the sequelae of rubella infection. Now that more is known of vaccine characteristics and the impact of the initially chosen strategies has been assessed, it is time to modify immunisation strategies, the priorities being first to protect women of childbearing age, and then to interrupt transmission of rubella.

Adolescent↗

Evaluation of varicella-zoster immune globulin: protection of immunosuppressed children after household exposure to varicella.

Varicella-zoster immune globulin (VZIG), an immunoglobulin prepared from normal donor plasma selected for high titer of antibody to varicella-zoster virus (VZV), and zoster immune globulin (ZIG), prepared from the plasma of donors convalescing from herpes zoster, were compared in a double-blind, randomized clinical trial to determine their relative efficacy in protecting immunosuppressed children from severe varicella. VZV infection occurred in 49 (60.4%) of 81 recipients of VZIG and in 57 (68.6%) of 83 recipients of ZIG. These rates and the clinical severity of varicella were not significantly different; however, the subclinical infection rate was significantly higher in ZIG recipients (31.3% vs. 16.0%). This difference was accounted for by a subgroup of patients receiving immunosuppressive therapy for nonneoplastic diseases. Doubling the dose of VZIG administered reduced the rate of subclinical infection. These data indicate that VZIG can be used to protect immunosuppressed children from severe chicken pox.

Chickenpox↗

Prevention of rubella transmission in medical facilities.

The widespread use of rubella vaccine in the United States has dramatically decreased the number of rubella cases and has prevented epidemics. Nevertheless, outbreaks of rubella continue to occur in medical facilities and have become important in the transmission of the disease. Control of outbreaks requires isolation of infectious patients, assignment of immune staff only to infectious patients, exclusion from work of infectious personnel, special follow-up of pregnant women and exposed persons, and the rapid vaccination of susceptible staff. Implementation of hospital rubella prevention programs is preferable to controlling an outbreak. The vaccination of all susceptible personnel provides the opportunity for preventing rubella outbreaks, disruption of hospital services, and fetal rubella infection.

Adult↗

Assessment of susceptibility to measles and rubella.

We conducted a serological and questionnaire study of 755 US Merchant Marine Academy cadets (aged 16 to 29 years) and their parents to determine the cadets' susceptibility rate to measles and rubella and to see if there was any difference in the accuracy of cadet and parental histories of previous infection and vaccination. Approximately 4% of the cadets were susceptibility. We also determined the costs and the effectiveness of three alternative strategies for vaccinating susceptible adolescents and young adults: (1) vaccinating all persons regardless of past history; (2) serologically screening all persons and vaccinating only those who were susceptible; and (3) vaccinating all individuals who do not have physician-documented proof of proper vaccination, past infection (measles only), or serological immunity. The cost savings among the three alternatives are dependent on the proportion of potential vaccinees with records available for review and must be balanced against the proportion of susceptible persons protected by each alternative. We also found that a combined vaccination program for both measles and rubella is less costly than a program aimed at providing immunity to only one of the two diseases.

Adolescent↗

A benefit-cost analysis of mumps vaccine.

Applying benefit-cost analysis, we determined the savings in morbidity, mortality, and costs of mumps vaccination in the United States. Using reported mumps incidence rates in a model cohort of 1 million persons followed up for 30 years, mumps vaccination would prevent more than 74,000 cases of mumps and three deaths. Approximating the actual incidence rate of mumps, by assuming that 90% of people are infected by age 30 and 60% of these have had clinical illness, mumps vaccination would prevent more than 540,000 cases of mumps and 23 deaths. A mumps vaccination program, in which mumps was given as part of a measles-mumps-rubella combination, would reduce costs associated with mumps by more than 86%, with a benefit-cost ratio of 7.4:1, using reported incidence rates. The program has a benefit-cost ratio of 39:1 when approximations of actual mumps incidence are used in the analysis. Mumps vaccination is highly cost beneficial.

Cost-Benefit Analysis↗

Fetal risk associated with rubella vaccine.

Ninety-four susceptible women received either Cendehill or HPV-77 rubella vaccine. All gave birth to healthy infants. Seventeen susceptible women received the RA 27/3 vaccine. All their infants were free of abnormalities compatible with congenital rubella, as were 54 born to mothers of unknown immune status at the time of RA 27/3 vaccination and those later found to be immune. An additional susceptible woman received an unknown strain of vaccine; she also had a healthy infant. The risk of severe congenital malformations after rubella vaccination is low. In our 112 cases, the maximum risk was approximately 3%. Concern about the potential adverse effects of rubella vaccine on the fetus should not interfere with vaccination of women of childbearing age. However, since the actual risk may not be zero, women known to be pregnant should not be vaccinated, and conception should be avoided for three months after vaccination.

Adolescent↗