Despite nationwide measles vaccination coverage in Israel of over 90%, repeated outbreaks of measles have spread from isolated communities with poor immunization uptake. Some severely affected individuals were children under 1 year of age, including premature infants. We evaluated the serological status of 195 newborn infants and their 161 mothers divided into four groups: vaccinated mothers (VMs) and premature infants, VM and full term infants, naturally immunized mothers (NIMs) and premature infants, NIM and full term infants. Maternal and cord blood measles antibody titers were determined by haemagglutination inhibition (HI) test and microneutralization test (mNT). Fewer than 40% of preterm infants of VM and less then 70% of preterm infants of NIM had protective titers at birth. The results of this study may aid in formulating new measles vaccination recommendations for preterm infants.

West Nile virus (WNV) caused disease outbreaks in Israel in the 1950s and the late 1970s. In 1998 an outbreak of WNV in goose farms and evidence of infection in dead migratory birds were reported. Consequently, human diagnostic services for WNV were resumed, including virus isolation, serology, and RT-PCR. Risk factors for infection were assessed by a serological survey in 1999, which revealed a seroprevalence of (a) 86% in people who had close contact with sick geese, (b) 28% in people in areas along bird migration routes, and (c) 27% in the general population. Following two fatal cases in Tel Aviv in September 1999 and one encephalitis case in the southern Eilot region, a regional serological survey was initiated there. The survey revealed two more WNV-associated acute encephalitis cases, an IgG seroprevalence of 51%, and an IgM seroprevalence of 22%. In the summer of 2000, acute cases of WN disease were identified in the central and northern parts of Israel, involving 439 people. The outbreak started in mid-August, peaked in September, and declined in October, with 29 fatal cases, primarily in the elderly. During the outbreak, diagnosis was based on IgM detection. Four virus isolates were subsequently obtained from preseroconverted frozen sera. Sequence and phylogenetic analysis of 1662 bases covering the PreM, M, and part of the E genes revealed two lineages. One lineage was closely related to a 1999 Israeli bird (gull) isolate and to a 1999 New York bird (flamingo) isolate, and the other lineage was closely related to a 1997 Romanian mosquito isolate and to a 1999 Russian human brain isolate.

BACKGROUND:In trials comparing different formulations of measles vaccine, excess non-specific mortality occurred in female children who received high titer vaccine. These findings suggest a gender-specific effect of measles vaccine.OBJECTIVES:To determine whether gender differences exist in the rates of adverse reactions and morbidity in the month following immunization with measles-containing vaccine, and to evaluate whether there is a gender-specific association between the humoral immune response to measles vaccination and post-vaccination morbidity.METHODS:Parents completed questionnaires on the health status of 755 infants aged 15-20 months, during the month preceding and the month following the measles-mumps-rubella vaccination. Blood samples were tested for measles antibody titers in a subsample of 237 infants.RESULTS:After controlling background morbidity in the infants, the relative risk of fever and rash following vaccination was 2.35 in females and 1.36 in males. The geometric mean antibody titers against measles were similar in both sexes and there was no significant association between antibody titer and post-vaccination morbidity in either sex.CONCLUSIONS:Our findings demonstrate higher rates of adverse effects in females following vaccination with MMR vaccine, irrespective of the humoral response. This study emphasizes the need to consider possible gender differences when evaluating new vaccines.

In order to evaluate the true immune status and the effect of revaccination on a young adult population, we collected serum samples from 289 military recruits who were vaccinated during an outbreak in 1991. Most vaccinees, age 18-25 years, had apparently been immunized once before as infants. Sera collected just prior to the vaccination and 14 and 28 days afterwards were tested for measles antibodies by hemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA)-IgM.Before vaccination, 46 (15.9%) of the subjects had no HI antibodies, (< 1 : 4) and 48 (16.6%) had borderline (1 : 4) HI titer. Following vaccination, only ten (3.5%) remained negative and 19 (6.6%) had borderline titer. The increase in HI antibody titer was inversely proportional to the prevaccination titer, and 159 subjects (55.0%) showed no increase at all. The geometric mean titer (GMT) rose from 9.14 to 21.47. Among the prevaccination-negative subjects (HI < 1 : 4) 28 (60.9%) reached a postvaccination titer of greater than or equal to 1 : 8, and eight (17.4%) reached a titer of 1 : 4. Twelve (26.1%) of the negative subjects seroconverted and developed IgM, 16 (35%) seroconverted without IgM, and 18 (39%) remained negative and did not develop IgM.A group of eight vaccinees with prevaccination titer of greater than or equal to 1 : 4 developed IgM. Some were probably infected by the circulating wild-type virus prior to the vaccination. Thus, a total number of 20 of the 289 subjects studied (6.9%) had true negative preimmune status as judged by the IgM test. However, the vaccination campaign prevented further measles cases, apparently by increasing the population's immunity, particularly in individuals with very low titers or without measles antibodies. (C) 1996 Wiley-Liss, Inc.

Background: Determination of the immune status against measles in young adults requires careful evaluation of the laboratory methods because of waning immunity. The hemagglutination inhibition (HI) test and enzyme-linked immunosorbent assay (ELISA) may lack the sensitivity required to detect very low levels of antibodies. In addition, the correlation between ELISA-IgG assays and the degree of protection from measles is not well defined.

A 25-year-old man was admitted following deterioration in behavior and onset of blindness. He soon became comatose and died 6 weeks later. Brain biopsy showed nuclear inclusion bodies resembling viral capsids, astrocytosis and perivascular lymphocytic cuffing but no demyelination. The diagnosis of subacute sclerosing panencephalitis was made on finding: measles virus antigens in both serum and cerebrospinal fluid, the identification of measles RNA sequences in brain tissue by the polymerase chain reaction, and intense, oligoclonal, IgG-banding in the CSF. However, the relatively advanced age of the patient, the absence of myoclonus and the nondistinctive EEG profile lacking synchronous bursts of high-voltage slow and sharp waves, are unusual.

The introduction of live attenuated measles vaccine in Israel during 1967 dramatically decreased the incidence of measles. However, cases still occur in periodic outbreaks and epidemics, with an increasing proportion of infants and children younger than 2 years of age. We examined the decay of maternally derived measles antibody during the first year of life in the Jewish population of Israel which represents a highly vaccinated population with immunization rates exceeding 90%. We used sera of healthy full term infants born in 1988 and 1989. Fifty specimens for each of the following age groups were used: 0 (cord blood), 2, 4, 6, 7 and 12 months. Three assays for each specimen were used: enzyme-linked immunosorbent assay (ELISA); hemagglutination-inhibition test (HI); and neutralization test (NT). Good correlation among all 3 tests was found. All cord blood specimens were positive by at least 2 assays. Seropositivity rates declined rapidly with age. Fifty percent of all 4-month-old infants and < 30% of all 6-month-old infants were positive by 1 test or more; at 12 months of age none of the tested specimens was positive by HI or NT and only 1 of 50 infants was positive by ELISA. In infants younger than 6 months of age, 5 (22%) of 23 specimens negative both by ELISA and by HI were positive by NT, but in 6-month-olds, only 2 (7%) of 28 negative by ELISA and HI were positive by NT, and in 12-month-olds none was positive. The results from southern Israel are similar to those obtained in North America and provide evidence that infants older than 6 months of age in a well-immunized population may be poorly protected against measles. On the basis of this information and epidemiologic data, the Israel Ministry of Health has recommended lowering the immunization age for measles, mumps and rubella from 15 months to 12 months.

BACKGROUND:Following vaccination of children using high-titre live measles vaccine, excess non-specific mortality was reported, particularly among females. Since vaccination with live measles virus results in a temporary depression of the immune response to other antigens, the female predominance in subsequent non-measles mortality may be due to sex differences in response to live measles vaccines.METHODS:In this study, the immunogenicity of standard titre live Schwarz strain measles vaccine was examined 2 and 4 weeks post-vaccination in 223 males and 66 female aged 18-20 years in Israel in 1991.RESULTS:Females had higher post-vaccination geometric mean titre (GMT) at all levels of pre-vaccination titres at both 2 and 4 weeks. Furthermore, after controlling for differences in pre-vaccination titres, overall the post-vaccination GMT for females was about 50% higher than for males (P < 0.001).CONCLUSIONS:These findings indicate that females exhibit a stronger humoral immune response to measles vaccine. Possible sex differences in immunosuppression following measles vaccination should be explored.

Measles morbidity and mortality in Israel have declined since the introduction of routine vaccination, even though measles continues to occur in epidemic cycles. In this study we examined the antibody response to measles revaccination, and the effect of prior administration of immune serum globulin (ISG) on the antibody response to measles vaccine. A study group of 312 young adults in army service received the Schwartz strain measles vaccine. Serum antibody levels were studied prior to vaccination and 2 and 4 weeks after vaccination. The finding of this study show that: a) booster response occurs in those vaccinees shown to have low or undetectable prerevaccination titers of measles antibodies; b) there is no effect of administration of ISG, prior to vaccination, on the antibody response to measles vaccine; and c) at the present level of immunity to measles in the Israeli adolescent population, we still may witness periodic epidemics in populations at risk.