Israel Medical Association Journal

Background: Anti-influenza vaccination has proven cost-effective for society. In Israel, however, vaccination rates remain relatively low in comparison to other countries.

Objectives: To analyze the socioeconomic and health status factors affecting the decision to be vaccinated against flu and to compare these factors to results from other countries in order to determine which segments of the adult population should be targeted for increased coverage in influenza vaccination programs.

Methods: Our source was the 1999/2000 Health Survey of the Central Bureau of Statistics for the group aged 25 and above, comprising 16,033 individuals. We used statistical methods such as the Probit regression model to estimate the effects of socioeconomic and health status variables on the decision to get a flu shot. The variables included gender, age, marital status, education, ethnic origin, religious affiliation and housing density, as well as chronic illnesses, smoking, hospitalizations, membership in health management organizations and kibbutz membership.

Results: Our findings indicate that being a post-1990 immigrant from the former Soviet Union, living in a densely populated house, being unmarried and smoking heavily are important factors in predicting the decision not to be vaccinated. In contrast, chronic illness, previous hospitalizations, older age, and kibbutz membership have a positive effect on the decision to take the vaccine.

Conclusions: It is necessary to identify the socioeconomic and health variables marking population sectors that are less likely to be vaccinated in order to design a suitable policy to encourage vaccination.

Objectives: To estimate usual patterns of acute illness in the community as a baseline for integration into pandemic influenza and bioterrorism preparedness plans.

Methods: Between 2000 and 2003 we conducted 13 telephone surveys to estimate the usual incidence and prevalence of symptoms of acute illness in the community.

Results: On average, 910 households were included in each of the surveys, representing about 3000 people. The compliance rates for full interviews ranged from 72.3% to 86.0%. In winter, on average, about 2% of the Israeli population (individuals) suffered each day from fever of ≥ 38ºC, and about 0.8% during the other months. The prevalence of cough was higher, 9.2% in winter and 3% during summer. Daily incidence of fever ranged from about 0.4% per day in winter to about 0.2% in the fall. The prevalence and incidence of both fever and cough were highest for infants followed by children aged 1–5 years.

Conclusions: These background morbidity estimates can be used for planning the overall treatment requirements, in addition to actual cases, resulting from pandemic influenza or a bioterrorist incident.

Background: The evaluation of influenza vaccine activity and potency are based on the immune response to hemagglutinin, and protection is indicated when a ≥ 1:40 titer of hemagglutination inhibition serum antibody is present. Neuraminidase, the second surface glycoprotein, may also have a role in protection, but little information on the immunologic response to this component is available.

Objectives: To determine whether any response to neuraminidase is evoked by intranasal immunization with a novel, whole, inactivated anti-influenza vaccine.

Methods: This study was part of a more comprehensive study of mucosal and serum immune response to this vaccine. Fifty-four young adults were immunized intranasally, 9 intramuscularly and 18 received a placebo. Twenty-three elderly people were immunized intramuscularly, and 21 elderly and 17 children were immunized intranasally. Serum and nasal antibodies to antigens N1 and N2 were determined by the lectin neuraminidase test.

Results: Serum response following intranasal vaccination was lower than after intramuscular vaccination, and ranged from 21.4 to 35.3% and 33.3 to 64.7% following intranasal vaccination and 52.2 to 77.8% and 47.8 to 88.9% after intramuscular vaccination, to N1 and N2 respectively. Nasal antibody response was low and was found only after intranasal vaccination, and response to N2 was better than to the N1 antigen.

Conclusions: It may be beneficial if future vaccines would include competent hemagglutinin and neuraminidase, which would afford a higher level of protection.
 

Various events occurring during pregnancy might influence the normal neurogenesis of fetus brain, including exposure to the influenza virus. Several studies have attempted to find a relationship between exposure to influenza virus and the onset of schizophrenic behavior in childhood or adulthood, however results remain contradictory. In this review we describe several animal and human studies that show or do not show a relationship between exposure to the influenza virus during pregnancy and the subsequent development of schizophrenia.

Background: Upper respiratory tract illnesses have been associated with an increased risk of morbidity and mortality.

Objective: To assess the influence of vaccination against influenza on the risk of hospitalization in internal medicine and geriatric wards, and the risk of death from all causes during the 2000–2001 influenza season.

Methods: A historical cohort study was conducted using computerized general practitioner records on patients aged 65 years and above, members of “Maccabi Health Care Services” – the second largest health maintenance organization in Israel with 1.6 million members. The patients were divided into high and low risk groups corresponding to coexisting conditions, and were studied. Administrative and clinical data were used to evaluate outcomes.

Results: Of the 84,613 subjects in the cohort 42.8% were immunized. At baseline, vaccinated subjects were sicker and had higher rates of coexisting conditions than unvaccinated subjects. Vaccination against influenza was associated with a 30% reduction in hospitalization rates and 70% in mortality rates in the high risk group. The NNT (number needed to treat) measured to prevent one hospitalization was 53.2 (28.2 in the high risk group and 100.4 in the low risk group). When referring to length of hospitalization, one vaccine was needed to prevent 1 day of hospitalization among the high risk group. Analyses according to age and the presence or absence of major medical conditions at baseline revealed similar findings across all subgroups.

Conclusions: In the elderly, vaccination against influenza is associated with a reduction in both the total risk of hospitalization and in the risk of death from all causes during the influenza season. These findings compel the rationale to increase compliance with recommendations for annual influenza vaccination among the elderly.

Background: Each winter influenza activity is a major cause of morbidity and mortality both in Israel and worldwide.

Objectives: To identify the influenza viruses active in Israel during the winter season and to assess the extent of influenza morbidity.

Methods: Information was collected on a population of 18,684 individuals enrolled in two community clinics in central Israel. It included the total number of visits for acute respiratory infection – including influenza and influenza-like illness (ARI/flu-like) – during a 20 week surveillance period (23 November 1997 to 27 March 1998) and the percent of influenza virus isolates in nasopharyngeal specimens from a sample of patients with ARI/flu-like collected on a weekly basis during the same period.

Results: A total of 5,947 visits for ARI/flu-like were recorded among 18,684 enrolled patients in two community clinics (18.1%). The progressive increase in the number of visits for ARI/flu-like reached a peak on week 2/98 with 597 visits and a rate of 31.95 visits per 1,000 population. After this, a decrease to the initial values was evident by week 12/98. Most affected patients were in the age groups 5–14 and 65 years and over, with a rate of 733.5 and 605.3 visits per 1,000 population, respectively. Influenza virus was isolated from 92 of the 426 nasopharyngeal specimens (21.6%). The most commonly detected strain was A/Sydney/5/97(H₃N₂) like (77.2%). The peak rate of isolates was recorded at the beginning of January (01/98).

Conclusions: A/Sydney/5/97(H₃N₂) like-strain was the dominant influenza virus. Its presence did not prevent the simultaneous activity of influenza A/H₁N₁ virus. The dynamic of the clinical disease as expressed by the weekly visit rate for ARI/flu-like was similar to the temporal pattern of the virological findings. The extent of morbidity suggests moderate epidemic activity.
 

Methods: The study was conducted in the three general hospitals in Haifa City, and in five nursing homes in the Haifa subdistrict. Self-administered questionnaires were distributed to 1,014 employees of whom 71% were females, 34% were nurses, 27% were physicians and 28% were non-professional workers.

Results: The crude response rate was 66%. Response rates were higher in females (71%) than in males (49%), in nurses (70%) than in physicians (43%), and in staff of internal and pediatric departments than in workers of surgery departments and emergency rooms. The overall vaccination rate among the respondents was 11%, which was higher among males (15%) than among females (10%). No significant relationship between vaccination rate and age, occupation and department was found. The vaccination rate among employees with chronic illness was very low (7%). Influenza vaccine was actively recommended to 29% of the employees. The main reasons for non-compliance were low awareness of the severity of the disease and of the vaccine's efficacy and safety, and unavailability of the vaccine within the workplace.

Conclusions: Educational efforts and offering the vaccine at the workplace at no cost are the most important measures for raising influenza vaccination rates.

Objective: To identify correlates for under-utilization of influenza immunization among the elderly.

Methods: A telephone survey was conducted among a random sample of patients aged 65 and over registered at a Jerusalem primary care community clinic. The 626 questionnaires were analyzed for associations of immunization receipt for the latest influenza season. Multivariate logistic regression was performed to identify independent correlates. Respondents were also asked what factors had influenced their decision about immunization.

Results: The most frequently reported influence on getting immunized was a physician's recommendation. Immunization was independently associated with the identity of the primary care physician (P0.0001) and with having visited the physician during the previous 3 months (P=0.0006). Immunization was more likely among persons who believed that it provides complete protection from influenza (P0.0001) and less likely among those who believed immunization can cause influenza (P0.0001). Higher immunization rates were also associated with being married (P=0.0031).

Conclusion: Through their influence on patient knowledge and the effect of their recommendation, primary care physicians play a pivotal role in determining immunization rates. Physicians should routinely discuss the effects of immunization and recommend it to the elderly.

Background: Although influenza is usually a mild self-limiting disease it can cause serious complications in high risk groups. The economic costs of influenza are large due to the burden on the health system and absenteeism from work. There is evidence that the vaccine is underused in groups targeted for vaccination.

Objectives: To estimate: a) the compliance rate with the influenza vaccination in Israel during the winter seasons of 1998/1999 and 1999/2000, b) the role of health care personnel and the media in influencing compliance, and c) the reasons for lack of compliance in the elderly.      

Methods: Two national population-based random telephone surveys of 1,500 households were performed during October 1999 and January 2000 to survey influenza vaccination compliance prior to the winters of 1998/1999 and 1999/2000 respectively. Each survey was performed during four successive evenings. The response rate was 78.1% for the first survey and 79.1% for the second.

Results: Vaccination compliance was similar in both surveys. The average rate of vaccination was 6% for the population under 65 years and 50% for the population of 65 years and above. The overall vaccination rate was around 10%. The family physician was the main authority to recommend the vaccination, followed by the community nurse. Absence of recommendation and lack of faith in the efficacy of the vaccine were the main reasons for non-compliance.

Conclusion: Compliance rates with influenza vaccine in targeted groups in Israel remain relatively low. Health care personnel should be more involved in promoting the vaccine.