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N A Halsey

Publications and source records attributed to N A Halsey.

At least 19 recordsLinked to original sources
PubMed1992

Sexual behavior, smoking, and HIV-1 infection in Haitian Women.

OBJECTIVE: To determine whether a previously observed association between human immunodeficiency virus type 1 (HIV-1) infection and smoking in Haitian women could be explained by confounding high-risk behaviors. DESIGN AND SETTING: A nested case-control study at a primary care health clinic in Cité Soleil, Haiti. PARTICIPANTS: Women who reported having smoked (n = 89) and randomly selected nonsmokers (n = 329) who had participated in a survey 1 to 12 months earlier evaluating risk factors for HIV-1 infection. MAIN OUTCOME MEASURES: Lifetime sexual practices, smoking, health beliefs and practices, and other factors potentially confounding the relationship between smoking and HIV-1 infection. RESULTS: Compared with nonsmokers, smokers reported higher rates of high-risk behaviors, including more lifetime sex partners (P less than .001), being less likely to be married (P less than .01), and being more likely to have visited folk healers (P less than .01). No intravenous drug use was reported, and no significant differences were noted between smokers and nonsmokers in numbers of past surgical or dental procedures or injections. Adjustment for all factors associated with HIV-1 infection and smoking in regression analyses revealed an independent association between smoking and HIV-1 infection (odds ratio [OR], 3.4; 95% confidence interval [Cl], 1.6 to 7.5). Other factors associated with HIV-1 infection included having more than two life-time sex partners (OR, 3.4; 95% Cl, 1.7 to 6.8) and lower socioeconomic status as reflected by a dirt floor in the home (OR, 8.6; 95% Cl, 3.3 to 22.0). CONCLUSIONS: Smoking is a marker for high-risk sexual behavior and is associated with an increased risk of HIV-1 infection in this population. The persistent association between smoking and HIV-1 infection after adjustment for all known risk factors suggests the possibility of a biologic effect of smoking that warrants further evaluation in other populations.

Adult↗
PubMed1992

Dose-response to acellular pertussis vaccine and comparison with whole cell pertussis vaccine at 15-24 months and 4-6 years of age. Acellular Pertussis Vaccine Study Team.

In a randomized double-blind trial 55 children of 15-24 months and 56 children of 4-6 years of age previously immunized with whole-cell DTP (WC-DTP) received acellular pertussis DTP vaccines containing 12.5 micrograms (AC-12.5) or 25 micrograms (AC-25) each of pertussis toxoid (PT) and filamentous haemagglutinin (FHA) per dose of WC-DTP. No differences in antibody responses or adverse events were noted for children who received AC-25 as compared with AC-12.5. All three groups had significant increases in pertussis agglutinins, but the geometric mean titre (GMT) for 4-6-year-old children who received WC-DTP was higher than the GMT for children who received acellular vaccine. No significant differences were noted in the GMT of antibodies to FHA or PT between children who received WC-DTP and recipients of acellular vaccine. The rates of several adverse reactions were significantly (p less than or equal to 0.05) higher for recipients of WC-DTP, and children given WC-DTP were significantly (p less than or equal to 0.00001) more likely to have received acetaminophen. These acellular vaccines are safe and as immunogenic for FHA and PT as WC-DTP when administered as the fourth or fifth dose to children who received three doses of WC-DTP in infancy. The lower (12.5 micrograms) dose of acellular vaccine was as effective as the higher (25 micrograms) dose in inducing antibodies to FHA and PT in children 15-24 months and 4-6 years of age.

Antibodies↗
PubMed1992

Seroprevalence of human immunodeficiency virus type 1 among pregnant women.

Five (0.74%) of 678 women delivering in 1985 at a tertiary referral hospital for high-risk pregnancies and 16 (1.34%) of 1198 women visiting an urban prenatal obstetrics clinic in 1986-1987 had serologic evidence of human immunodeficiency virus type 1 (HIV-1) infection. Unlinked testing (removal of personal identifiers from the blood specimen and the epidemiologic data sheet) of residual serum from hepatitis B virus serologic testing was used. Neither age, marital status, payor status, nor serologic markers of hepatitis B virus infection was useful in identifying women at risk for HIV-1 infection. As a result of these data, we have initiated a program in which counseling is offered to all women and testing for those who consent. Unlinked testing of women who refuse consent is performed for epidemiologic purposes. This will allow us to continue to plan for health care resource needs and to track the course of the epidemic in various subgroups of pregnant women.

Adult↗
PubMed1992

Tuberculin skin test reactivity among adults infected with human immunodeficiency virus.

Infection with the human immunodeficiency virus type 1 (HIV-1) results in decreased cell-mediated immunity, which includes decreased delayed hypersensitivity to skin test antigens. HIV-1 seropositivity and skin test reactivity to purified protein derivative (PPD) were determined among 2042 healthy Haitian adults with normal chest radiographs. Among HIV-1-seropositive individuals, 52.3% (146/279) had PPD reactions greater than or equal to 10 mm compared with 67.2% (1184/1763) of the seronegative adults (P less than .001). However, the percentage of HIV-1-seropositive individuals with PPD reactions greater than or equal to 5 mm was similar to the percentage of seronegative adults with PPD reactions greater than or equal to 10 mm (180/279 [64.5%] vs. 1184/1763 [67.2%]). Assuming that the rate of prior infection with Mycobacterium tuberculosis was similar for HIV-1-seronegative and -seropositive populations, these data provide support for the recent recommendations to use induration of greater than or equal to 5 mm as evidence of past infection with M. tuberculosis in HIV-1 seropositive adults.

Adult↗
PubMed1992

Herpes simplex virus type 2 infection, syphilis, and hepatitis B virus infection in Haitian women with human immunodeficiency virus type 1 and human T lymphotropic virus type I infections. The Johns Hopkins University (JHU)/Centre pour le Developpement et la Santé (CDS) HIV Study Group.

Antibodies to herpes simplex virus type 2 (HSV-2), antibodies to hepatitis B virus (HBV) core antigen (anti-HBc), and VDRL antibodies (serologic evidence of syphilis) were evaluated in women known to be infected with human immunodeficiency virus type 1 (HIV-1) (n = 95) or human T lymphotropic virus type I (HTLV-I) (n = 45) and controls (n = 89). HIV-1-seropositive women were more likely than controls to have antibodies to HSV-2 (88% vs. 54%; P less than .001), anti-HBc (67% vs. 43%; P = .008), and VDRL antibodies (21% vs. 8%; P = .02). Similarly, HTLV-I-seropositive women were more likely than controls to have antibodies to HSV-2 (82% vs. 54%; P = .003) and anti-HBc (67% vs. 43%; P = .008). There was no evidence that HIV-1 or HTLV-I predisposed to chronic hepatitis B virus infection. The stronger associations between HIV-1 and HTLV-I with HSV-2 than the associations with syphilis or HBV are consistent with the hypothesis that recurrent disruptions of mucous membranes caused by HSV-2 infections predispose to sexual transmission of HIV-1 and HTLV-I.

Adolescent↗
PubMed1992

Lack of association between maternal antibodies to V3 loop peptides and maternal-infant HIV-1 transmission.

We investigated the association between maternal antibodies to HIV-1 peptides in pregnant women and the acquisition of HIV-1 infection by their offspring. Pregnant HIV-1-infected Haitian women were tested for the presence of antibodies against peptides of 14-17 amino acid length from the V3 loop region of strains IIIb and MN. Antibody testing was performed in two separate laboratories by enzyme-linked immunosorbent assay (ELISA). Peptides from four regions of the V3 loop were synthesized in several different laboratories and the purity confirmed by high performance liquid chromatography (HPLC). The mothers of infants who acquired HIV-1 infections did not differ significantly from the mothers of uninfected infants in the prevalence or concentration of antibodies to any of the 15 peptides evaluated. Additional studies are indicated to determine if neutralizing antibodies or other immunologic parameters are associated with maternal-infant HIV-1 transmission.

Amino Acid Sequence↗
PubMed1991

The A/Mallard/6750/78 avian-human, but not the A/Ann Arbor/6/60 cold-adapted, influenza A/Kawasaki/86 (H1N1) reassortant virus vaccine retains partial virulence for infants and children.

Characteristics of avian-human (ah) and cold-adapted (ca) influenza A/Kawasaki/9/86 (H1N1) reassortant vaccine viruses were compared in 37 seronegative adults and 122 seronegative infants and children. The 50% human infectious dose (HID50) in infants and children was 10(2.9) and 10(2.6) TCID50 for the ah and ca vaccine, respectively. The ah influenza A/Kawasaki/9/86 reassortant was reactogenic: 24% of infants and children infected with greater than or equal to 100 HID50 had fever greater than or equal to 39.4 degrees C. Since H3N2 ah vaccines were previously shown to be adequately attenuated, it is reasonable to suggest that the genes that code for hemagglutinin and neuraminidase of the H1N1 virus apparently influence the reactogenicity of reassortant viruses derived from the avian influenza A/Mallard/New York/6750/78 donor virus. Because this avian virus does not reproducibly confer a satisfactory level of attenuation to each subtype of influenza A virus, it is not a suitable donor virus for attenuation of wild-type influenza viruses. In contrast, the ca A/Ann Arbor/6/60 donor virus reliably confers attenuation characteristics to a variety of H1N1 and H3N2 influenza A viruses.

Adult↗
PubMed1991

Safety and immunogenicity of human rotavirus vaccine strain M37 in adults, children, and infants.

Rotavirus vaccine strain M37 (serotype 1), recovered from the stool of an asymptomatic newborn infant and serially passaged in cell culture, was given orally to adults, children, and infants. Serologic responses were detected by neutralization assay or EIA in 59% of 17 adults (10(5)-pfu dose), 55%-60% of 21 infants and children (10(4)-pfu dose), and 70% of 10 infants (10(5)-pfu dose), vaccine virus was shed by 24%, 20%-36%, and 70%, respectively. In adults, neutralizing antibody rises to strain M37 and the related serotype 1 strain Wa occurred with equal frequency (41% vs. 47%). In pediatric subjects, the former were more frequent (36%-40%) than the latter (10%-18%). This was also true of 8 infants who received two doses of vaccine. Mild gastrointestinal illnesses occurred with equal frequency in pediatric subjects who received vaccine or placebo. Thus, strain M37 was well tolerated and immunogenic in young infants, but elicited primarily vaccine-strain-specific rather than serotype-specific neutralizing antibody responses.

Adult↗
PubMed1991

Successful immunization of infants at 6 months of age with high dose Edmonston-Zagreb measles vaccine. Cite Soleil/JHU Project Team.

A group of 2097 Haitian infants 6 to 11 months of age were randomized to receive Schwarz or Edmonston-Zagreb strain measles vaccines containing 10- to 500-fold more vaccine viral particles than standard potency vaccines. No unusual adverse reactions were noted. Edmonston-Zagreb vaccines were more effective than equivalent doses of Schwarz vaccines as measured by the proportion of vaccinated children with measles antibody concentrations greater than or equal to 200 mIU/ml 2 months after vaccination and the persistence of antibody at 18 to 24 months of age. High titer Edmonston-Zagreb vaccine administered at 6 months of age induced antibody concentrations greater than or equal to 200 mIU/ml in 83% of infants by plaque reduction neutralization and 93% of infants by enzyme-linked immunosorbent assay with high rates of antibody persistence at 12 to 24 months of age. The World Health Organization recommends high titer Edmonston-Zagreb measles vaccines for routine use at 6 months of age in areas where measles is an important cause of mortality in young infants.

Antibodies, Viral↗
PubMed1991

Differences in antibody response to whole-cell pertussis vaccines.

It has been assumed that whole-cell pertussis vaccines (WCVs) commercially distributed in the United States are of comparable immunogenicity, as all must comply with established standards for licensure. However, we have recently noted significant differences in antibody responses between groups of infants receiving the two WCVs commercially available in the United States. In separate studies performed concurrently under similar protocols at Vanderbilt and Johns Hopkins universities, infants were randomized to receive either an acellular pertussis vaccine or WCV. The acellular pertussis vaccine used at the two sites was identical, but the WCVs were from different manufacturers. Antibody responses to acellular pertussis vaccine did not differ between the two studies; responses to WCV differed dramatically, with infants receiving the Lederle WCV producing a 46-fold increase in antibody to pertussis toxin, compared with a 2.4-fold increase for infants receiving the Connaught WCV (P = .00003). Evaluation of other comparative data sets that were available provided further support for the conclusion that the two commercially available WCVs consistently differed in their ability to induce antibody to pertussis toxin. These findings have important implications for the design and interpretation of clinical trials comparing acellular and WCV products.

Adhesins, Bacterial↗
PubMed1990

Comparison of live attenuated cold-adapted and avian-human influenza A/Bethesda/85 (H3N2) reassortant virus vaccines in infants and children.

Randomized, placebo-controlled studies with 10(3)-10(7) 50% tissue-culture infectious dose (TCID50) of avian-human (ah) and cold-adapted (ca) influenza A/Bethesda/85 (H3N2) reassortant viruses were completed in 106 seronegative young children 6-48 months of age. Although the reassortants differed in six of eight RNA segments, they exhibited similar properties in level of attenuation, infectivity, immunogenicity, and efficacy. The 50% human infectious dose was 10(4.6) TCID50 for ah and 10(4.4) for ca vaccines. Both reassortants were satisfactorily attenuated with restricted replication and were no more reactogenic than placebo. The mean peak titer of virus shed was 10(1.5) (ah) to 10(2.0) (ca) TCID50/ml, and each of 37 isolates tested retained their characteristic vaccine phenotypes. Infection with ah or ca virus conferred immunity to experimental challenge with homologous virus. These findings indicate that both ah and ca influenza A/Bethesda/85 (H3N2) reassortants should be suitable vaccine candidates for use in healthy infants and young children.

Antibodies, Viral↗
PubMed1990

Childhood survival in Haiti: protective effect of measles vaccination.

To evaluate the impact of measles vaccination on survival of children residing in a periurban slum in Haiti, a total-population survey was conducted 2.5 years after completion of a one-time study of the serologic response to measles vaccine administered in the same population. Pregnancy histories from the 16,400 women in the population revealed that 1499 children had been born during a 7-month interval that would have made them eligible for participation in the measles vaccine program. Of these children, 1381 (92.1%) survived to 9 months of age, the median age that measles vaccine had been administered. Seventy-three infants had died between 9 and 39 months of age. Mortality of infants who were seronegative before receiving measles vaccine was significantly lower (P = .0013) than that of unvaccinated infants (3/235 vs 70/1056, respectively). Other factors positively associated with survival between 9 and 39 months of age included socioeconomic status (P = .0002), maternal literacy (P = .0020), maternal knowledge and use of oral rehydration solution (P = .0002), and an interval of greater than 24 months to the birth of the next younger sibling (P = .0012). Multivariate stepwise logistic regression analysis was used to evaluate the independent association of measles vaccination by adjusting for other factors that also correlated with survival and that might have been associated with maternal seeking of vaccinations.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMed1990

HIV-1 in Haitian women 1982-1988. The Cite Soleil/JHU AIDS Project Team.

Pregnant Haitian women (n = 4,474) residing in a periurban slum were interviewed to identify risk factors for sexually transmitted diseases and sera were tested to identify antibodies to HIV-1 and syphilis. The seroprevalence rates for antibodies to HIV-1 increased from 8.9% in 1986 to 9.9% in 1987 and 10.3% in 1988. Sera obtained in 1982 from 533 mothers of young infants in the same community revealed that 7.8% were HIV-1 seropositive. Of women pregnant for the first time in 1986-1988, 6.6% were HIV-1 seropositive and 6.0% had a positive VDRL. The highest seropositivity rates (greater than 15%) were noted in women 20 to 29 years of age with a history of two or more sexual partners in the year prior to pregnancy. Factors independently associated with HIV-1 seropositivity in pregnant women by logistic regression analysis included being unmarried, age 20-29 years, having had more than one sex partner in the year prior to pregnancy, a positive serologic test for syphilis, and smoking. A dose-response effect was noted in the association between HIV-1 seropositivity and smoking. The association between smoking and HIV-1 infections could be confounded by unrecognized behavioral factors or due to a biologic effect of smoking. The continuing high HIV-1 seropositivity rates in pregnant women indicate that current preventive measures are insufficient and increased control efforts are urgently needed.

Blotting, Western↗
PubMed1990

Human immunodeficiency virus neutralizing antibodies in sera from North Americans and Africans.

Neutralizing antibodies (NAs) against four isolates of human immunodeficiency virus type 1 (HIV-1) were assayed in HIV-1 antibody positive sera from the United States, Haiti, Zimbabwe, and Zaire. Overall, there were NAs detected in 95, 81, 60, and 73% of sera with reciprocal geometric mean titers (GMTs) of 626, 23, 10, and 20, respectively, against HIV-1MN, HIV-1IIIB, HIV-1RF, and HIV-1Z3. Sera from North America had significantly higher NA titers against HIV-1MN. In each country, the highest antibody titers observed were against the MN strain. Otherwise, sera from the U.S. neutralized most strongly HIV-1IIIB, sera from Zaire neutralized most strongly HIV-1Z3, and sera from Zimbabwe had equal titers against all three viruses. The differences between countries were reflected in analyses of NA titers of subgroups classified on the basis of clinical status, indicating that the differences were not likely to be related to differences in clinical status of the patients being tested. Some of this antigenic variation is reflective of known genetic diversity, while some is not. The results suggest that undefined preserved and variable regions containing neutralization epitope(s) exist. These data do not indicate a need to define antigenic subtypes of HIV-1 at present. The existence of conserved neutralization epitope(s) may indicate the potential for broad immunogenicity of appropriately selected vaccine antigens.

AIDS-Related Complex↗