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Biomedical subjects

D Nalin

Publications and source records attributed to D Nalin.

17 recordsLinked to original sources
PubMed2001

Control of hepatitis A through routine vaccination of children.

CONTEXT: The impact of routine hepatitis A vaccination of children living in large communities with elevated disease rates has not been evaluated. OBJECTIVE: To determine the effect of routine vaccination of children on disease incidence in a community with recurrent hepatitis A epidemics. DESIGN, SETTING, AND PARTICIPANTS: Community-based demonstration project conducted from January 12, 1995, through December 31, 2000, in Butte County, California, among children aged 2 to 17 years. INTERVENTION: In 1995, vaccination was offered to children aged 2 to 12 years during vaccination clinics conducted on 2 occasions 6 to 12 months apart at most schools in the county. In 1996-2000, vaccine was distributed to community health care clinicians, who vaccinated eligible children without charge. Vaccine was also available at health department clinics, selected child care centers, and other sites. MAIN OUTCOME MEASURES: Hepatitis A vaccination coverage, hepatitis A incidence, and vaccine effectiveness. RESULTS: During the study period, 29 789 (66.2%) of an estimated 44 982 eligible children received at least 1 vaccine dose; 17 681 (39.3%) received a second dose. The number of hepatitis A cases among the entire county population declined 93.5% during the study period, from 57 cases in 1995 to 4 in 2000, the lowest number of cases reported in the county since hepatitis A surveillance began in 1966. The 2000 incidence rate of 1.9 per 100 000 population was the lowest of any county in the state. Of the 245 cases reported during the 6-year period, 40 (16.3%) occurred among children 17 years of age or younger, of which 16 (40%) occurred in 1995 and only 1 in 2000. One of the 27 case patients eligible for vaccination had been vaccinated, having received the first dose 3 days before symptom onset. The estimated protective vaccine efficacy was 98% (95% confidence interval, 86%-100%). CONCLUSIONS: In this population, hepatitis A vaccine was highly effective in preventing disease among recipients. Childhood vaccination appears to have decreased hepatitis A incidence among children and adults and controlled the disease in a community with recurrent epidemics.

Adolescent↗
PubMed2000

Measles vaccine immunogenicity and antibody persistence in 12 vs 15-month old infants.

HYPOTHESIS: Maternal measles immunity in the United States today is primarily vaccine induced, with corresponding lower antibody titers in infants, as compared to infants born in an earlier era to mothers with naturally acquired measles immunity. We hypothesized that, due to lower titer of passively transferred maternal measles antibody, administration of measles vaccine at 12 months of age would result in seroconversion and antibody persistence comparable to vaccination at 15 months of age. POPULATION: Children at both an urban hospital and a suburban clinic. METHODS: Informed consent was obtained from mothers for the infants to receive M-M-R(R)II vaccine at either 12 or 15 months and to have serum samples obtained before vaccination and 4 weeks post-vaccination (PV). Between 9 and 39 months PV, a third serum sample was obtained from 28% of seroconverters. A diary of adverse experiences was kept for 3 weeks PV. Sera were assayed by a microneutralization assay (NT) and an enzyme immunoassay (EIA) for measles antibody. RESULTS: Both age groups tolerated vaccination well with minor and transient side effects. Forty-four of 47 (94%) 12-month-old infants seroconverted by NT, compared to 45 of 46 (98%) 15-month-olds (p=NS). There was no statistically significant decline in median NT titers or EIA titers in nineteen 12-month-olds and thirteen 15-month olds followed for 9-39 months PV. CONCLUSION: This study showed comparable serologic responses in 12- vs 15-month-old infants born to measles vaccine-immune mothers; however, the sample size was too small to have adequate power and further study is indicated. Titers of antibody were constant in both the 12-month-old and the 15-month-old infants, over a 9-39 month period, suggesting that waning immunity over this period of time is not a problem in either age group.

Age Factors↗
PubMed1998

Immune response to measles vaccine in 6-month-old infants of measles seronegative mothers.

Determinants of measles vaccine-induced immune response in infancy include maternal immune status and the infant's age at immunization. In a previously published study, 74% of 19 6-month-old infants developed neutralizing antibody. Two of the infants were born to measles seronegative mothers. In order to (1) assess the prevalence of measles seronegativity in a population of US mothers born after 1960 and (2) assess the immunogenicity of standard titer measles vaccine in 6-month-old infants of measles seronegative mothers, mothers with healthy term (> or = 37 weeks gestation) infants attending well child care clinics at MetroHealth Medical Center were prospectively screened for measles antibody by EIA. If negative, maternal samples were retested for neutralization (NT) antibody. Fifteen of 169 women were seronegative by both assays. Six-month-old infants of 9 of these 15 seronegative mothers were enrolled in the pediatric vaccine study. Serological response of these 9 infants to monovalent measles vaccine (Attenuvax) was compared to the responses of 17 6-month-old infants of seropositive mothers and 15 15-month-old toddlers from our previous study. All 9 infants of seronegative mothers became EIA seropositive after the vaccine compared to 9 of 17 6-month-old infants born to seropositive mothers (p = 0.02). Differences in NT seroconversion rates (100% vs 70.6%) were not statistically significant. The comparison group of 15-month-old vaccinees showed 100% seroconversion by both assays. The NT geometric mean titer (GMT) was higher in the 15-month-old toddlers than in the 6-month-old infants born to seronegative mothers (87.2 vs 33.9, p < 0.01), suggesting age-related differences in humoral immune response unrelated to passively transferred maternal antibody.

Antibodies, Viral↗
PubMed1998

A dose response study of hepatitis A vaccine in healthy adults who are > or = 30 years old and weigh > or = 77 kg.

The dose response relationship of 25-, 50-, and 100-U doses of an inactivated hepatitis A vaccine was examined in 358-seronegative volunteers in a 2-dose schedule. The 50-U and 100-U groups had statistically significantly higher seroconversion rates than the 25-U group at weeks 2, 4, 8, and 24. Seroconversion was statistically significantly greater for the 100-U compared with the 25- and 50-U doses 2 weeks after the first injection but was not significantly different by 4 weeks after the first injection in the 50- and 100-U dose groups. After 2 injections, all subjects in all groups seroconverted. The vaccine was well tolerated at all dosage levels.

Adult↗
PubMed1997

The effect of age and weight on the response to formalin inactivated, alum-adjuvanted hepatitis A vaccine in healthy adults.

Formalin-inactivated, alum-adsorbed, hepatitis A vaccine was evaluated in 100 healthy adults who were stratified at enrollment into two age groups: 18-39 years: n = 50; 40-65 years: n = 50. All individuals received vaccine at 25 U of viral antigen. After stratification, both groups were randomized to receive either vaccination at 0 and 24 weeks or vaccination at 0.2 and 24 weeks. Subjects were bled for serology at 0, 2, 4, 24, 28 weeks and 1 year. The seroconversion rate and geometric mean titer (GMT = mIU ml-1) after one dose of vaccine was lower for older subjects [second week: < 40 years: 15/25 (60%) (GMT: 12.9). > 40 years: 5/22 (23%) (GMT: 6.1): fourth week: < 40 years: 20/22 (91%) (GMT: 29.0), > 40 years: 16/23 (70%) (GMT: 14.3)]. After a second dose at 2 weeks the seroresponse improved so that there were no longer differences between age groups [24 weeks: < 40: 21/22 (95%) (GMT: 123.9), > 40: 22/23 (96%) (GMT: 106.1)]. A third dose at 24 weeks resulted in a 20-40-fold increase in GMT in both age groups. As a separate evaluation height, weight, skin fold thickness, and body mass index (BMI) were assessed by logistic regression for their ability to predict serologic response. Serologic response was significantly associated with lower weight (P = 0.032) and BMI (P = 0.024) but not with height or skin fold thickness. Hepatitis A vaccine was well tolerated, with no serious adverse experiences. Adults older than 40 years appear to respond less well than younger adults to a single dose of 25 U of hepatitis A vaccine but equally well after two doses of vaccine. The slower antibody response to hepatitis A vaccine in overweight individuals was not attributable to skin adipose tissue.

Adolescent↗
PubMed1995

Saliva and serum as diagnostic media for antibody to hepatitis A virus in adults and in individuals who have received an inactivated hepatitis A vaccine.

Saliva was evaluated as a diagnostic fluid for screening individuals for evidence of previous hepatitis A virus (HAV) infection and for evidence of seroconversion after vaccination with inactivated hepatitis A vaccine. A new and simple saliva collection method and an assay for detection of HAV antibody were used; the assay used an antibody capture format. There was complete concordance between the results of saliva-based assays and those of serum-based assays, both of which were used for determining previous natural HAV exposure. However, for vaccine recipients, 100% concordance for saliva-based and serum-based assays occurred only at serum titers of > 9,000 mIU/mL, which were determined with use of the modified HAVAB assay. Saliva provides adequate sensitivity and specificity for determining naturally acquired HAV infection, although it is not useful in clinical trials for determining seroconversion after HAV vaccination.

Adult↗
PubMed1994

Immunogenicity, safety and tolerability of varying doses and regimens of inactivated hepatitis A virus vaccine in Navajo children.

The Navajo are known to be at high risk for hepatitis A virus (HAV) infection. This study investigated the safety and immunogenicity of an investigational, alum-adjuvanted, formalin-inactivated HAV vaccine (VAQTA) developed by Merck Research Laboratories in Navajo children. One hundred two of 212 children, ages 4 to 12 years, were HAV-seronegative (< 10 mIU/ml by an enhanced sensitivity modification of the HAVAB; Abbott). Ninety of these children received the HAV vaccine. Study participants were given vaccines containing various viral protein concentrations: Group A (n = 18), 6 units; Group B (n = 36), 13 units; and Group C (n = 36), 25 units HAV protein (1 unit approximately 1 ng viral protein antigen). Three-dose (0, 8, 24 weeks) and two-dose (0, 24 weeks) regimens were compared in subgroups within B and C. The vaccine was well-tolerated and there were no serious adverse reactions; no vaccinee developed hepatitis A. After 1 dose 82 to 100% of children seroconverted (> or = 10 mIU/ml, modified HAVAB; Abbott) and 100% seroconverted after 2 doses. After 1 dose the geometric mean titer for antibody was: Group A, 22 mIU/ml; Group B, 18 mIU/ml; and Group C, 38 mIU/ml. After 3 doses geometric mean titers increased to 10,106 mIU/ml in Group A, 7258 mIU/ml in Group B and 11,856 mIU/ml in Group C. Further field studies are indicated to evaluate its use in high risk populations, such as the Navajo.

Age Factors↗
PubMed1993

Sensitive assays for hepatitis A antibodies.

Two commercial assay kits for detecting antibody to hepatitis A virus (anti-HAV) have been modified in order to increase their sensitivity. These modifications are made by less dilution of the test serum, in the case of Abbott HAVAB-M assay, or by an increase in the volumetric ratio of the test serum to the labeled anti-HAV in the case of the Abbott HAVAB assay. These modifications result in 5- to 20-fold increases in test sensitivity and enable the detection of anti-HAV at 2-3 weeks following vaccination. The earlier detection of anti-HAV is important to vaccine development in assuring the presence of antibody levels in travelers sooner after vaccination.

Adult↗
PubMed1993

Inactivated hepatitis A vaccine in childhood: implications for disease control.

The experience to date with the Merck inactivated hepatitis A vaccine in healthy children 2-16 years old is reviewed. Comparison of response to increasing doses indicates that an intramuscular dose of 25 units results in seroconversion of 99% of children by week 4 following a single dose. Antibody persistence rate is nearly 100% six months later, whether or not a second priming dose is given at week 8. This vaccine has proven highly immunogenic in children and has a favourable safety/tolerability profile. It should be useful for pre-exposure prophylaxis and control of hepatitis A, and should eventually replace immune globulin (Ig) for this indication.

Adolescent↗
PubMed1992

Safety profile and immunogenicity of an inactivated vaccine derived from an attenuated strain of hepatitis A.

To determine the safety and immunogenicity of an inactivated hepatitis A vaccine, 56 healthy adult volunteers were randomly assigned to receive an intramuscular injection of 6.3, 12.5 or 25 ng of inactivated hepatitis A vaccine or placebo at 0, 2 or 4, and 24 weeks. Adverse reactions occurred with similar frequency in vaccine and placebo recipients and consisted primarily of pain or tenderness at the injection site. By 4 weeks after a single 6.3, 12.5 or 25 ng injection, seven, nine and ten out of ten vaccinees, respectively, had antibody detectable by a HAV AB assay modified to increase its sensitivity tenfold. All vaccinees had antibodies detectable by this assay within 2 weeks of their second inoculation. Geometric mean antibody levels increased with higher doses of vaccine (p = 0.05). Neutralizing antibody was detected within 4 weeks of a single inoculation in all vaccinees. Neutralizing antibody was detected after the third inoculation at dilutions of greater than or equal to 1:2048 in all 12.5 and 25 ng vaccinees. All 19 vaccinees tested at 24 months still had HAV antibodies detectable by a modified HAV AB assay. This inactivated hepatitis A vaccine appears to be well tolerated and immunogenic at doses of 6.3-25 ng. The choice of dose and vaccination schedule may depend on the rapidity with which seroconversion is desired.

Adolescent↗
PubMed1991

Safety and immunogenicity of a live attenuated hepatitis A virus vaccine in seronegative volunteers.

Seronegative adults were enrolled in a dose-escalating study of a live attenuated hepatitis A virus (HAV) vaccine that was prepared from the F' variant of HAV strain CR326F. They were injected subcutaneously with 10(4.1), 10(5.2), 10(6.1), or 10(7.3) TCID 50 of HAV vaccine (n = 40) or with placebo (n = 12) and were followed for 6 months. None of the vaccine recipients developed significant systemic reactions or aminotransferase elevations. HAV was not isolated in cell culture from any postvaccination serum or stool specimen tested. Antibody to HAV was detected by modifications of HAV antibody assays (HAVAB or HAVAB-M) in 20%, 40%, 60%, and 100% of the recipients of each vaccine dose, in ascending order. Neutralizing antibody was present in all 10(7.3) TCID50 recipients tested at 3 and 6 months after vaccination. This live attenuated HAV vaccine was well tolerated and highly immunogenic at a dose of 10(7.3) TCID50.

Adult↗
PubMed1979

Oral rehydration of neonates with dehydrating diarrhoeas.

Thirty-nine of forty neonates with mean dehydration equivalent to 6.7% of body-weight were orally rehydrated with a glucose/electrolyte solution. Only one patient required any intravenous fluids for rehydration. Hypernatraemia and acidosis present at admission were corrected within a few hours without complications. It seems that oral rehydration, is suitable for neonates as well as for children and adults.

Administration, Oral↗