Israel Medical Association Journal

Immunization coverage is a major health indicator. In Israel, routine childhood immunizations are provided at community public well-baby clinics. Immunization monitoring is an important cornerstone of a national health policy however, data obtained through sampling carries the risk of under-representation of certain population strata, particularly high risk groups. Despite high national average immunization coverage, specific sub-populations are under-immunized, as highlighted by outbreaks of vaccine-preventable diseases. The mean national immunization coverage at age 2 years (2006 data) was: DTaP[1]-IPV[2]-Hib4[3] (all 93%), HBV[4]3 (96%), MMR1[5] (94%), HAV1[6] (90%). These reports are based on a 17% population-based sample in some districts and on cumulative reports in others. A national immunization registry requires data completeness, protection of confidentiality, compulsory reporting by providers, and links to other computerized health records. It should provide individual immunization data from infancy to adulthood and be accessible to both providers and consumers. In 2008 the Israel Ministry of Health launched a national immunization registry based on immunization reporting from well-baby clinics using a web-based computerized system. As of January 2010, 120 well-baby clinics are connected to the nascent registry, which includes the records of some 50,000 children. The implementation of a comprehensive national immunization registry augurs well for the prospect of evidence-based assessment of the health status of children in Israel. 

 
[1] DTaP = diphtheria-tetanus-acellular pertussis

[2] IPV = inactivated polio vaccine

[3] Hib = Haemophilus influenzae b

[4] HBV = hepatitis B virus

[5] MMR = measles-mymps-rubella

[6] HAV = hepatitis B virus

The human papillomavirus family of viruses causes a variety of benign, premalignant and malignant lesions in men and women. All cervical cancers are caused by HPV[1]. It is the leading cause of death from cancer in women in developing countries; every year some 493,000 women develop cervical cancer and 230,000 women die every year of this disease. The vaccine against HPV includes virus-like particles, composed of the major viral capsid protein of HPV without the carcinogenic genetic core. Large-scale studies have shown that the vaccine is tolerated well, leads to high antibody levels in both men and women, and prevents chronic HPV infection and its associated diseases. To achieve effective coverage the vaccine should be given prior to sexual debut. Introduction of the vaccine into specific countries, particularly Israel, should take into account the local incidence of cervical cancer as well as the increasing incidence of precancerous cervical lesions and genital warts, which reduce quality of life and are associated with considerable costs.

Background: Poliovirus rapidly evolves by nucleic acid substitutions and genetic recombination with other polioviruses and non-polio enteroviruses. Evolving oral poliovirus (Sabin strains) can rapidly revert to neurovirulence and undergo antigenic alterations.

Objectives: To evaluate the threat of vaccine-derived poliovirus (1–15% divergence from the respective Sabin strain) for a poliomyelitis-free population in a country with a long-standing routine vaccination program.

Methods: We characterized genetic and antigenic changes in OPV[1] strains isolated from sewage in Israel and evaluated intestinal immunity by measuring fecal excretion after OPV challenge of vaccinated children.

Results: Characterization of poliovirus from sewage revealed eight type 2 and three type 3 vaccine polioviruses that had replicated and started to evolve (vaccine that replicated and diverged by 0.5 to ≤ 1.0%) and nine highly diverged type 2 vaccine-derived polioviruses (1–15% divergence from the respective Sabin strain) with 8–14% divergence between the years 1998 and 2005. Six of the eleven VRPV[2] uniquely recombined with OPV and/or NPEV[3]. The nine VDPV[4] were epidemically related, genotypically neurovirulent, and had 10–15 amino acid substitutions in antigenic sites altering their antigenicity, but shared a single recombination. Type 2 OPV was excreted by 23% and 17% of infants challenged with OPV 3 months after partial immunization (two doses each of OPV and enhanced inactivated poliovirus) or full immunization (three doses of each) respectively, despite high humoral antibody titers.

Conclusions: Our findings, which show that OPV is excreted for a significant period by children with high humoral immunity, emphasize the long-term potential threat from VDPV in highly vaccinated populations. An adequate immunization program, combined with environmental surveillance, is necessary to prevent poliomyelitis and community transmission of poliovirus. 

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.
 

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: Previous data showed that new recombi­nant hepatitis B virus vaccine, which contains the S-protein component of the HBV surface together with the Pre-S₁ and Pre-S₂, is considerably more immunogenic than a second-generation recombinant I-IBV vaccine.

Objectives:To compare the immunogenicity and safety of a novel recombinant HBV vaccine S1, Pre-S₁ and Pre-S₂ protein components of the hepatitis B surface antigen - Bio­TM

Hep^TM 10 לg dose, to a licensed vaccine containing only the S-protein component - Engerix-B, 20 לg dose.

Methods: A prospective randomized study included 524 adults - 260 in the Bio-Hep group and 264 in the Engerix-B group. Both vaccines were administered in a three-dose regimen given at 0, 1 and 6 months, and adverse events were recorded on a diary card 5 days after each vaccination. lmmunogenicity was tested by measuring anti-hepatitis B surface antibody.

Results: One month after the third injection, 98% of the BioHep^TM subjects were found to be seroprotected vs. 85.1% of the Engerix-B group. In addition, the geometric mean titers were 2,203 mlU/ml and 326 mlU/ml in the Bio-Hep-B and Engerix-B groups respectively. An immunogenic advantage of Bio-Hep-B was suggested by the rapid onset of antibody response - 66.5% were seroconverted one month after the first injection as compared to 19.3% in the Engerix-B group. No unexpected adverse events were observed, and the recorded events were mild in both groups.

Conclusions: BioHepTM, a novel recombinant HBV vaccine containing 5, Pre-S₁ and Pre-S₂ protein components. at a lower dose, is safe and more immunogenic than the conventional HBV vaccine that contains only S protein.

Background: High dose interleukin-2 therapy, adminis­tered in bolus, is considered to be a reasonable treatment option in a selected group of patients with metastatic malignant melanoma.

Objectives: To present our experience using this mode of therapy in 21 patients with metastatic melanoma.

Materials and Methods: The 21 patients in our study group comprised 13 men and 8 women with a mean age of 46 years (range 29-63). Their metastatic disease was present in all extracranial sites, dermal and sub-dermal metastases being the most common (15 patients had at least one site, in addition to other locations of metastases). Patients with intracranial disease were excluded due to the poor effectivity of IL-2 at this site. Treatment comprised a course of 2 weeks of therapy with a 1 week rest interval between. Radiological and physical evaluation was performed 6-8 weeks after the first course. If a response was achieved a second course of therapy was given. Patients received up to 14 planned doses of IL-2 in each week, 720,000 lU/kg of IL-2 per dose iv. in 15 minutes. All treatments were given in the surgical ward, and only one patient was hospitalized in the intensive care unit.

Results: Of the 21 patients, one had a complete response that has lasted for 17 months and 5 patients had a partial response (range 3 months to 3 years). One patient died during treatment, and one patient who refused further treatment because of no response died a few days after completion of treatment. Prior to therapy three of the responders had received autologous vaccines with good immunological response (P=0.115). Toxic side effects were significant, but they were treated successfully with no residual damage.

Conclusions: High dose IL-2 can be administered safely in a surgical department. The response rates achieved in this series justify the use of high dose IL-2 in a selected group of patients. To improve response rates, a combination of auto­logous vaccines prior to high dose IL-2 may be recommended.

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.