Mumps outbreak in Israel's highly vaccinated society: are two doses enough?

Mumps outbreaks in recent years have given rise to questions about the effectiveness of the mumps vaccine. This study examined the epidemiological data from a recent mumps outbreak in Israel and from outbreaks in other countries with high vaccination coverage, and considered whether long-established vaccination policies designed to protect against mumps are in need of revision. Of over 5000 case patients in the Israeli outbreak, half of whom were in the Jerusalem health district, nearly 40% were aged ≥15 years and, of those whose vaccination status was known, 78% had been fully vaccinated for their age - features similar to those in recent mumps outbreaks in Europe and North America. The epidemiological and laboratory evidence suggests that many previously vaccinated adolescents and young adults are now susceptible to mumps because their vaccine-based immunity has waned. Booster vaccination programmes for those at high risk of infection during mumps outbreaks - particularly those in congregate living environments - merit priority consideration.

The changing epidemiology of viral hepatitis A in Israel.

BACKGROUND: Between 1970 and 1979, there was an increase in the incidence of viral hepatitis in Israel with a shift of peak incidence to an older age in the Jewish population, followed by a declining trend during the early 1980s. In July 1999 universal immunization of infants against hepatitis A was introduced. OBJECTIVE: To evaluate the chan-ges in the epidemiology of viral hepatitis A in Israel during the past decade. METHODS: Viral hepatitis is a notifiable disease in Israel and cases are reported to the regional health offices, which in turn provide summary reports to the Ministry of Health's Department of Epidemiology. The data in this study were derived from the summary reports and from results of seroprevalence studies. RESULTS: Following the increase in the incidence of reported viral hepatitis (mainly due to type A) between 1970 and 1979, the rates then stabilized and around 1984 began to decline until 1992. Since then there has been a slight increase. Whereas until 1987 the rates were consistently higher in the Jewish population, since then they are higher in the Arab population. The shift in the peak age-specific incidence from the 1-4 to the 5-9 year age group observed in the Jewish population around 1970 occurred 20 years later in the Arab population. The previously described seasonality is no longer evident. Recent seroprevalence studies indicate that by age 18 years only about 30-40% of the Jewish population have anti-hepatitis A antibodies. CONCLUSIONS: The decline in the incidence of hepatitis probably reflects the changing socioeconomic condition occurring at different times in the two major population groups. Since hepatitis A accounts for almost all the acute viral hepatitis in Israel, the universal vaccination of infants introduced in 1999 should substantially lower the morbidity within the next few years.

Cost-benefit analysis of a nationwide infant immunization programme against hepatitis A in an area of intermediate endemicity.

BACKGROUND/AIMS: The availability of safe and effective Hepatitis A vaccines prompts an evaluation of a nationwide infant vaccination campaign to supplement strategies aimed at high-risk groups such as travellers and military personnel. METHODS: A spreadsheet model was used to estimate costs and benefits of a nationwide infant immunization programme against Hepatitis A for the period from 1997-2014 in Israel. RESULTS: Immunizing all one year olds in Israel from 1997-2014 would for a cost of $32.0 million to the health services and $42.1 million to society (including $10.1 million lost work and transport costs), reduce the number of cases of Hepatitis A during the next 45 years from 181,000 to 47,000. This would save $57.5 million in health service resources alone, $32.0 million in averted work absences and transport costs in addition to a further $17.0 million in averted premature mortality costs. The health service, resource and societal benefit:cost ratios are 1.80:1, 2.13:1 and 2.54:1, respectively. CONCLUSIONS: The recent adoption of a nationwide infant HAV immunisation policy in Israel is both medically and economically justifiable.

Epidemiological analysis of tuberculosis treatment outcome as a tool for changing TB control policy in Israel.

BACKGROUND: Sensing an inadequacy of tuberculosis control due to an influx of TB associated with immigration, we analyzed TB treatment outcome in Israel by population groups. OBJECTIVES: To provide an epidemiological basis necessary for any new national TB control policy, and to bring it to the attention of the medical profession in Israel and abroad since its results led to a change in Israel's TB control policy. METHODS: We reviewed all TB cases notified during the period 1990 to September 1992. "New cases" (820 cases, 93.5%) and "re-treatment cases" (57 cases, 6.5%) were analyzed according to three mutually exclusive groups: "successful outcome," "death," and "potentially unsatisfactory outcome" (according to WHO/IUATLD definitions). RESULTS: Of 820 "new cases," 26.6% had a "satisfactory outcome," 68.5% had a "potentially unsatisfactory outcome" and 4.9% died; compared to 47.4%, 45.6% and 7% among 57 "re-treatment cases," respectively. Using logistic regression analysis, outcome was associated with the district health office (P < 0.0001), the TB "experience" of the notifying clinic (P < 0.0001), and the form of TB (P = 0.02). No significant relationships were obtained for population groups, gender and age, interval between arrival in Israel and TB notification, and bacteriological results. CONCLUSIONS: Non-supervised TB treatment resulted in poor outcomes regardless of population groups. Better outcomes occurred in the larger TB clinics. Therefore, in addition to measures such as adequate drug supplies, reorganization of TB laboratories and training of TB personnel, we recommend the "directly observed treatment short-course" for all cases as well as reducing the number of treatment centers thereby increasing their case load.

[Introduction of routine hepatitis A immunization in Israel--the first in the world].

Notification of hepatitis A, which is endemic in Israel, has been compulsory since the establishment of the State. From 1992-98 an average of 2,600 cases were reported annually. Many infections are asymptomatic and mild, especially in children. In general, severity increases with age; in Western countries the case fatality rate is 1.5/1,000 among children less than 5 years old and 27/1,000 among those over 50. Until 1987 incidence in Israel was higher in Jews than in non-Jews, but since 1988 incidence has been about 50% higher in non-Jews. Among Jews highest age specific rates shifted from children 1-4 years old to children 5-9 years old in 1970, and in non-Jews in 1989. Improved sanitary conditions and personal hygiene have reduced very early childhood exposure and hence increased the proportion of susceptible older children and adults, in whom symptomatic disease is more prevalent. Israel is the first country in the world to include hepatitis A vaccine in its routine immunization schedule. The vaccine is given in 2 doses: at 18 months and 24-30 months of age, and there will be epidemiologic and serologic follow-up. A significant decrease in hepatitis A morbidity is expected in small children within 5 years. The percentage of reported cases in older children and in adults is expected to increase, although the absolute incidence among these groups will decrease.

The control of mumps in Israel.

BACKGROUND: Measles-mumps-rubella (MMR) vaccine replaced monovalent measles vaccine in the routine childhood vaccination schedule in Israel in December 1988, primarily to achieve the elimination of the congenital rubella syndrome. In this observational study, we report on changes in reported mumps incidence in Israel from the time of the introduction of MMR vaccine until the end of 1998. METHODS: The report is based upon passive national surveillance of mumps incidence, which has been notifiable in Israel since 1977. RESULTS: Reported mumps incidence in Israel is now less than 2% the pre-vaccine incidence. CONCLUSIONS: In the decade since the introduction of routine mumps vaccination in 1-year-olds in Israel, mumps control has been achieved. Although small outbreaks occur and may continue to occur in future years, because of under-vaccination of children, primary vaccine failure and waning immunity, it can tentatively be said that mumps is no longer a public health problem in Israel.

Clinical manifestations of Bordetella pertussis infection in immunized children and young adults.

STUDY OBJECTIVES: The incidence and prevalence of pertussis in adults have increased in recent years. It has been shown that previously immunized adults and adolescents are the main sources of transmission of Bordetella pertussis. The aim of this study was to describe the clinical presentation and the clinical course of pertussis in children and young adults who were immunized previously against B pertussis. DESIGN: Retrospective study. SUBJECTS: Children and young adults who were reported by local physicians to the Department of Epidemiology in the Israeli Ministry of Health with serologically confirmed pertussis and who were immunized previously were included. Information sought included personal data, epidemiologic data, signs and symptoms, laboratory results, initial diagnosis, and treatment. RESULTS: In the 95 previously immunized patients with serologically confirmed pertussis (mean age [+/- SD], 8.9 +/- 4.4 years old; range, 5 to 30 years old), the mean duration from onset of symptoms until the final diagnosis of pertussis was 23 +/- 15 days. The disease was usually atypical and generally mild. All the described patients had cough, usually prolonged, lasting 4 +/- 3.6 weeks. Only 6% had the classic whoop. The mean WBC count was 8.7 +/- 2.6 cells/mm6, and the lymphocyte count was 40 +/- 12%. Two patients were admitted to the hospital for severe pneumonia. Among the reported cases, the proportion of patients between the ages of 10 and 45 years increased from 6.5% during the period from 1971 to 1980, to 26% during the period from 1980 to 1990, and to 38% during a 1989 outbreak. CONCLUSIONS: Pertussis in previously immunized individuals is usually characterized by an atypical and relatively mild clinical course. Patients suffer mainly from a prolonged and persistent cough. Early diagnosis may lead to prompt administration of therapy. Prophylaxis of exposed persons might be effective in decreasing both severity and transmission of the disease.

Measles control in Israel: a decade of the two-dose policy.

BACKGROUND AND METHODS: The introduction of routine measles immunization in Israel in 1967 was followed by a 95% reduction in reported measles incidence. In 1990, a second measles immunization dose was instituted, and up until the end of 1999, 16 birth cohorts were offered the second dose. We present here changes in reported measles incidence in Israel following institution of the two-dose policy. RESULTS: First-dose coverage is 94%, and coverage for the second school-based dose exceeds 95%. A further 90% reduction in measles incidence has been observed and, following a modest national outbreak in 1994, measles incidence for 1995-99 stands at less than 3/100,000/year. CONCLUSIONS: Since measles is highly contagious, very high immunization coverage rates will be required to preserve these accomplishments, and measles elimination is still years away, but there is tentative evidence that measles containment is at hand. Even greater measles control can be anticipated as vaccine immunogenicity improves and successive cohorts of children come under the 2-dose regimen.

Screening for thyroid abnormalities among immigrants to Israel from the former USSR.

The exposure of some former Soviet citizens to radiation following the 1986 Chernobyl disaster has raised the question of the need to enroll these individuals in screening programs for thyroid abnormalities upon their immigration to Israel. Since screening programs have many drawbacks, and screening for thyroid disease has never been shown to decrease mortality or to improve survival, we are of the opinion that the establishment of thyroid screening programs will do more harm than good. The timely diagnosis of the very small excess in benign and malignant thyroid disease to be anticipated among the immigrants can be achieved in the community by the primary care physician armed with specific knowledge of the risks and the initial diagnostic approaches to suspected thyroid disease as well as information on the availability of specialist backup.

International epidemiological and microbiological study of outbreak of Salmonella agona infection from a ready to eat savoury snack--II: Israel.

OBJECTIVES: To explain an increase in the incidence of salmonellosis caused by Salmonella agona in Israel between October 1994 and January 1995 in the light of an outbreak of S agona phage type 15 infection in England and Wales caused by consumption of a ready to eat savoury snack produced in Israel. DESIGN: Epidemiology of S agona in 1994-5 was analysed and two consecutive, case-control studies of 32 and 26 case-control pairs were performed. Phage typing and molecular methods were used to characterise strains of S agona isolated from cases and samples of the snack in Israel and England and Wales. RESULTS: The increase in the incidence of S agona between October 1994 and January 1995 was countrywide. Cases of infection with group B salmonella increased from 60% to 80% in children under 5 years old. In both case-control studies, cases consumed more of the snack than did controls (4.25 v 2.94 packets per week in the first study (P = 0.086) and 4.04 v 2.37 packets per week in the second study (P = 0.034)). When the two studies were combined there was a significant dose-response relation for the number of packets consumed weekly. Compared with consumption of less than two packets, the odds ratio was 1.43 for between two and six packets and 3.37 for seven or more packets (chi 2 for trend = 5.27, P = 0.02) S agona phage type 15 was isolated from a packet of the snack sold in Israel, and the strain was identical with those isolated from packets and cases in Israel and England and Wales. CONCLUSIONS: This outbreak of S agona was caused by the contamination of a snack produced in Israel. Even under modern operating conditions, large, widespread international outbreaks of foodborne disease can occur. The success of this investigation resulted from excellent international collaboration between public health authorities.

Control of rubella in Israel: progress and challenge.

Despite a high-compliance school girl rubella immunization program since 1973 and a program for the immunization of women of childbearing age since 1980, sporadic cases of the congenital rubella syndrome (CRS) continue to occur in Israel, particularly following rubella epidemics. At highest risk for a child with CRS are unimmunized Arab women and immigrants from Ethiopia, although CRS has also occurred in infants of immunized non-immigrant women. In order to make progress towards the elimination of congenital rubella, the Israel Ministry of Health has incorporated into its rubella immunization program the intermediate goal of interrupting endemic rubella transmission in the country. To this end, universal rubella vaccination at age one began in 1989, a second dose at age six years was introduced in 1994, inclusion of boys in the program aimed at 12-year-olds began in late 1995, and catch-up campaigns to immunize never-immunized children, boys and girls, are planned. Moreover, women of childbearing age will be encouraged to receive a second dose of rubella vaccine. While the WHO goal of no indigenous CRS by the year 2000 will not be met, it is expected that in the coming decade substantial additional progress towards the elimination of CRS will be made.

Absence of an association between rubella vaccination and arthritis in underimmune postpartum women.

In a double-blind historical cohort study, 485 underimmune women who received rubella vaccine post-partum during 1985-1990 and 493 controls matched for age, place of residence and date of delivery were queried by phone concerning joint complaints following the pregnancy in question. Those reporting joint symptoms were invited for a personal interview at which joint symptoms and dates of their occurrence were explored in detail. Nineteen women in the vaccinated group (3.9%) and 16 from the control group (3.2%) were judged to have had joint symptoms compatible with the study definition of arthritis. The difference was not statistically significant. Thus, we were unable to find evidence for an association between rubella vaccination of underimmune adult women vaccinated post-partum and the subsequent development of arthritis. Rubella vaccine should continue to be used to immunize susceptible adult women against rubella in order to further the goal of elimination of the congenital rubella syndrome.

Decay of maternally derived measles antibody in a highly vaccinated population in southern Israel.

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.

Underutilization of influenza vaccine in Jerusalem.

BACKGROUND: Influenza is an annual winter disease which causes considerable morbidity in the general population and may be lethal in defined high-risk groups. A killed vaccine, recommended for the high-risk groups as well as for several occupational categories, is moderately protective against the disease, but vaccine sales suggest that use is low. METHODS AND RESULTS: In a hospital-based convenience survey of 295 persons belonging to groups for whom influenza vaccine is recommended, 78 (26.4%) reported having received the vaccine in 1989, and 74 (25.1%) in 1990. All vaccine recipients belonged to the 244 subjects eligible because of advanced age and/or chronic illness, giving vaccination rates in this group of 32.0% in 1989 and 30.3% in 1990. None of the 51 hospital doctors and nurses interviewed had received vaccine. Among the 244 eligible because of age or illness, vaccine receipt in 1990 was related to older age and number of risk factors, but even in subjects with three separate indications for receipt of vaccine, the vaccination rate was only 48%. Among persons advised by anyone to have influenza vaccine, 62.7% received vaccine in at least one of the two years, compared to a rate of 16.4% among subjects never advised to be vaccinated. Vaccine recommendation by a medical professional increased the vaccination rate to 69.3%. CONCLUSIONS: Influenza vaccine uptake in vaccine eligibles in Jerusalem is low, about 30% in the sick and elderly and considerably lower in medical personnel. Since influenza vaccination can save lives, it would be worthwhile to convince the medical profession to enthusiastically recommend this vaccine to high risk individuals and to explore novel ways of increasing uptake in the high-high risk groups such as persons in hospital or those residing in institutions.