The Association Between Depression and Invasive and In-situ Cervical Tumors: A Large Population Based Cohort Study.

BACKGROUND: Depression has been shown to be associated with cervical tumors (CTs), an association mostly demonstrated in studies in which temporality could not have been ascertained. OBJECTIVES: To study the association between depression and CTs and the influence of co-morbidities of this association in a large cohort study. METHODS: A retrospective computer-based cohort study was conducted. The cohort included 357,450 female members of Maccabi Healthcare Services. The cohort was classified as depressed or non-depressed using the International Classification of Diseases 9/10 codes. For each subgroup, demographic characteristics, behavioral characteristics, co-morbidities, and CTs diagnosis were obtained. The burden of co-morbidities was defined as the sum of major co-morbidities. We used zero-inflated negative binomial regression analysis due to over-dispersion to estimate the relative risk (RR) for CTs with 95% confidence interval (95%CI). RESULTS: Depression was diagnosed in 15,789 women. Among this group, CTs were diagnosed in 1585 (10.0%). Among the 341,661 non-depressed, CTs were diagnosed in 4185 (1.2%). After adjustment to age and socioeconomic status, the association between depression and CTs was RR=9.2 (95%CI 8.7-9.9, P-value < 0.0001). The association between depression and CTs increased as the burden of clinical conditions increased (P-value < 0.0001). CONCLUSIONS: Women with depression are at a higher risk for CTs, especially among those who have several co-morbidities. Tighter gynecology surveillance is crucial among these women.

Risk Factors for Multiple Infections with Salmonella, Shigella, and Campylobacter in Single Individuals Identified in Israel between 1999 and 2020: A Case-Case Control Study.

BACKGROUND: Salmonella, Shigella, and Campylobacter are highly prevalent among children. Reports on risk factors of patients infected with all three pathogens, not simultaneously, are scarce. OBJECTIVES: To identify risk factors for multiple infection with Salmonella, Shigella, and Campylobacter in the same child. METHODS: Using the Israel Sentinel Laboratory-Based Surveillance Network, we conducted a retrospective observational case-case-control study among children aged 0-9 years. A case was defined as a child infected with Salmonella, Shigella, and Campylobacter at different occasions between January 1999 and December 2020. A control was defined as a child infected with a single pathogen once, during the same period. Logistic regression models were applied to determine the association between multiple infections and demographic characteristics. RESULTS: We identified 109 cases (0.1%) infected with Salmonella, Shigella, and Campylobacter, and 86,511 controls (99.9%) infected with only one bacteria type. In a multivariable analysis, we showed that being Jewish (odds ratio [OR] 2.4, 95% confidence interval [95%CI] 1.3-4.4), having residency in Jerusalem (OR 3.2, 95%CI 1.3-7.7), or in the southern district (OR 3.7, 95%CI 1.5-8.8) were independent risk factors for multiple infection. CONCLUSIONS: Although very rare, non-simultaneous infection with multiple bacteria does occur in Israel. National and local authorities should promote programs to encourage proper hygiene practices, which are culture-adjusted.

Under-diagnosis of SARS-CoV-2 infections among children aged 0-15 years, a nationwide seroprevalence study, Israel, January 2020 to March 2021.

Until recently, children and adolescents were not eligible for COVID-19 vaccination. They may have been a considerable source of SARS-CoV-2 spread. We evaluated SARS-CoV-2 IgG antibody seroprevalence in Israeli children aged 0-15 years from January 2020 to March 2021. Seropositivity was 1.8-5.5 times higher than COVID-19 incidence rates based on PCR testing. We found that SARS-CoV-2 infection among children is more prevalent than previously thought and emphasise the importance of seroprevalence studies to accurately estimate exposure.

Microevolution and Patterns of Transmission of Shigella sonnei within Cyclic Outbreaks Shigellosis, Israel.

Whole-genome sequencing unveiled host and environment-related insights to Shigella sonnei transmission within cyclic epidemics during 2000-2012 in Israel. The Israeli reservoir contains isolates belonging to S. sonnei lineage III but of different origin, shows loss of tetracycline resistance genes, and little genetic variation within the O antigen: highly relevant for Shigella vaccine development.

The Clinical Significance of HPV Type in Women with Recurrent Cytological Atypia.

BACKGROUND: The human papillomavirus (HPV) test has proven to be efficient in triaging women with abnormal Pap findings in women with low cytological atypia, but there is no data about the accuracy for large loop excision of transformation zone in cases of recurrent atypia. OBJECTIVES: To assess the clinical correlation between results of HPV typing and conization histology in women who had recurrent abnormal Pap test results with no colposcopy findings. METHODS: Our retrospective cohort study included 138 women enrolled in the Maccabi Healthcare Services who had consecutive atypical Pap test results for 2 years in which no abnormal colposcopic findings were detected. These women had an HPV typing and then conization. RESULTS: Among the total study population (n=138), 71.7% had negative histology, 19.6% had ≤ cervical intraepithelial neoplasia grade 1 (≤ CIN1), and 8.7% had CIN2+. With regard to HPV typing, 34.8% were negative and 65.2% were positive. Of those testing positive, 34.4% were positive for HPV 16 or 18. Sensitivity, specificity, positive predictive value, and negative predictive values of HPV typing for women were 89.7%, 44.4%, 38.9%, and 91.7%, respectively, and for HPV 16 or 18: 71.4%, 67.7%, 32.3%, and 100.0%, respectively. After stratification by cytological grades, for women with high-grade cervical cytology, the sensitivity and negative predictive values of the HPV typing were higher than among low-grade cervical cytology, while specificity and positive predictive values were lower. CONCLUSIONS: HPV typing is a useful tool for the management of patients with persistently abnormal Pap test results.

[IMPLEMENTATION OF A NATIONAL SCREENING PROGRAM FOR DETECTION OF MALIGNANT AND PRE-MALIGNANT CERVICAL MORBIDITY IN ISRAEL].

INTRODUCTION: The natural development of cervical cancer, which takes many years, is mostly initiated by infection with human papillomavirus (HPV) and is characterized by the development of precancerous lesions, cervical intraepithelial neoplasia 3 (CIN3), which are defined as abnormal changes in epithelial cells that cover the cervix surface. Since the pre-cancerous process is microscopic and asymptomatic, early detection is based on cytological screening, the Pap test. In Israel, Pap tests are performed based on selfreferral for testing and not within the framework of a national screening program because of the low incidence rate of cervical cancer in Israel. The current program is characterized by low coverage rates, redundancy checks conducted on a small and selective group of women and therefore, lower efficacy in comparison to an organized, national program. In recent decades, the incidence rates of pre-malignant and malignant cervical morbidity showed increasing trends in Israel, an increase which can be stopped. Launching a national, organized program for the early detection of cervical cancer using Pap test and raising the awareness of women and physicians in Israel regarding the importance of this test, will increase the test uptake and decrease its current selectiveness. Furthermore, this will, in the short run, improve serious cervical morbidity, and in the long run, also reduce the incidence of precancerous and cancerous cervical lesions, as has been described in many countries in the world.

Trends in the Epidemiology of Campylobacteriosis in Israel (1999-2012).

The objective of this study was to examine the recent trends in the epidemiology of campylobacteriosis in Israel. A Sentinel Laboratory-Based Surveillance Network for Bacterial Enteric Diseases was established in Israel by the Israel Center for Disease Control (ICDC). This network generated data on subjects from whom Campylobacter spp. was isolated in community and hospital laboratories. Further characterization of the isolates was done at the Campylobacter National Reference Laboratory. Data from these two sources were integrated and analyzed at the ICDC. Between 1999 and 2012, 40,978 Campylobacter stool isolates were reported to the ICDC by the sentinel laboratories. The incidence rate of campylobacteriosis increased from 65.7 per 100,000 in 1999 to 101.7 per 100,000 in 2012. This increase resulted from a significant rise in the incidence of campylobacteriosis in the Jewish population which, since 2009, surpassed the consistent higher incidence of the disease in Israeli Arabs. The peak morbidity in Israel consistently occurred in late spring, with a risk excess in males compared with females, in younger age groups and earlier in the life span among Arabs than among Jews and others. These results suggest that further analytical studies should be carried out to identify risk factors responsible for the increased incidence of campylobacteriosis and better direct prevention and control of the disease in Israel.

Prevalence of hepatitis E virus antibodies, Israel, 2009-2010.

We investigated prevalence of hepatitis E virus in a sample of the population of Israel. The overall seroprevalence of antibodies to the virus was 10.6% (95% CI 8.4%-13.0%); age-adjusted prevalence was 7.6%. Seropositivity was associated with age, Arab ethnicity, low socioeconomic status, and birth in Africa, Asia, or the former Soviet Union.

Recent trends of cervical cancer and Cervical Intraepithelial Neoplasia 3 (CIN3) in Israel.

PURPOSE: This study describes time trends of cervical cancer and Cervical Intraepithelial Neoplasia 3 (CIN3) in Israel in the years 1986-2010 and characterizes these patients by demographics. METHODS: A retrospective survey based on cervical cancer and CIN3 data documented in the computerized system of the second largest Health Maintenance Organizations (HMO) in Israel, "Maccabi Healthcare Services" (MHS) between 1986 and 2010. RESULTS: 737 cervical cancer patients and 3,459 patients of CIN3 were reported between 1986 and 2010. The mean age of women with cervical cancer was significantly higher (mean 49.1 years) than that of CIN3 patients (mean 36.3 years) (p-value < 0.0001). The annual age-adjusted incidence rate of cervical cancer increased significantly from 1.6 per 100,000 in 1986 to 3.7 per 100,000 in 2010 (p for trend = 0.0001) and for CIN3, from 3.9 per 100,000 in 1986 to 40.4 per 100,000 in 2010 (p for trend = 0.0001). For cervical cancer, using the Joinpoint software we demonstrated an increase in the age-adjusted incidence rate between 1986 and 2003 and since then, a decrease was observed. Cervical cancer and CIN3 were mostly common in the Tel Aviv District. CONCLUSIONS: Although quite low to begin with, the incidence rates of cervical cancer and CIN3 in Israel may be further lowered by implementing an organized screening program and introduction of the HPV vaccine into the national immunization program.

Prevalence and correlates of human papillomavirus genotypes among patients with cervical cancer and cervical intraepithelial neoplasia 3 in Israel.

OBJECTIVES: This study aimed to assess the prevalence of human papillomavirus (HPV) in Israeli patients with cervical cancer and cervical intraepithelial neoplasia 3 (CIN3), to describe the distribution of the virus genotypes among positive cases, to characterize patients positive to HPV and, in particular, patients positive to HPV-16 and/or -18, and to evaluate the possible contribution of implementing HPV vaccination in Israel. METHODS: Samples from 84 patients with cervical cancer and 886 patients with CIN3, archived at the Maccabi Institute of Pathology, were screened for HPV. DNA extraction was performed using DNeasy Blood and Tissue Kit/QIAGEN. HPV detection and typing were performed by multiplex polymerase chain reaction with primers E6/E7, using the f-HPV/Genomed kit. RESULTS: Of the samples from 84 patients with cervical cancer, 89.3% were positive for HPV. Among these positive samples, HPV-16 was found in 70.7% and HPV-18 was found in 9.3%. Of the samples from 886 patients with CIN3, 85.0% were positive for HPV. Among these positive samples, HPV-16 was found in 73.8% and HPV-18 was found in 1.1%. In the patients with CIN3, the prevalence of HPV genotypes 16 and/or 18 was higher among young women and decreased across age groups. In addition, age, being born in Israel, being born in Europe, and being born in the former Soviet Union were correlated with a low risk of being infected with genotypes 16 and/or 18. DISCUSSION: The prevalence of HPV-16 and -18 in patients with cervical cancer and CIN3 in Israel is high. It is expected that the implementation of routine vaccination against these types of HPV will significantly reduce the burden of these diseases in Israel.

Laboratory challenges in response to silent introduction and sustained transmission of wild poliovirus type 1 in Israel during 2013.

Wild poliovirus type 1 (WPV1) introduction into southern Israel in early 2013 was detected by routine environmental surveillance. The virus was identified genetically as related to the South Asian (SOAS) R3A lineage endemic to Pakistan in 2012. Intensified, high-throughput environmental surveillance using advanced molecular methods played a critical role in documenting and locating sustained transmission throughout 2013 and early 2014 in the absence of any acute flaccid paralysis. It guided the public health responses, including stool-based surveillance and serosurveys, to determine the point prevalence in silent excretors and measured the effect of vaccination campaigns with inactivated polio vaccine and bivalent oral polio vaccine on stopping transmission.

Significant cross reactive antibodies to influenza virus in adults and children during a period of marked antigenic drift.

BACKGROUND: Little is known about the development of cross-reactive antibodies following natural exposure to pathogens. Such knowledge is critical in the development of new universal influenza vaccines. METHODS: To study the possibility of the presence of cross-reactive antibodies to influenza viruses which underwent a major antigenic drift between the years 1999 and 2007 sera from samples of 80 children and 400 adults were selected at random from the Israeli national serum bank. The sera was obtained in 2002 and in 2007, two time points that followed a major drift in the infectious H3N2 influenza virus strain (A/Panama/2007/99 to A/Wisconsin/67/2005). RESULTS: In the summer of 2002, 13% of the children had Hemagglutination Inhibition (HI) antibody titers of at least 40 and these antibodies recognized both A/Panama/2007/99 and A/Wisconsin/67/2005, where the latter strain only began to circulate in Israel in 2006. In 2007, 29% of the children had HI antibody titers of at least 40 directed against both A/Wisconsin/67/2005 and A/Panama/2007/99, even though they had never been exposed to the latter virus. Anti-A/Panama/2007/99 antibodies were detected in 58% and 68% of the 2002 and 2007 adult samples, respectively, while 8% and 39% had antibodies against A/Wisconsin/67/2005, respectively. CONCLUSIONS: The presence of naturally occurring cross-reactive influenza virus antibodies in a significant percentage of children has important implications for the development of a universal influenza vaccine.

Cervical Pap screening among Israeli women, 2005-2010.

PURPOSE: This study describes the distribution and the trends of cervical abnormalities in Israel, based on Pap smear results. METHODS: A retrospective analysis of cervical smears received by the Central Pathology Laboratory of Maccabi Healthcare Services between January 2005 and December 2010. RESULTS: In total, 711,541 Pap smears were screened in the study period. Cytological abnormalities were observed in 4.78% of the total smears screened. An increase was observed in the rate of positive results from 2.63% in 2005 to 6.78% in 2010 (p = 0.0026). The cervical abnormalities in the study period distributed as follows: atypical squamous cell (ASC)-2.72%, low-grade squamous intraepithelial lesion (LSIL)-1.54%, high-grade squamous intraepithelial lesion (HSIL)-0.34%, squamous cell carcinoma-0.01%, atypical glandular cells (AGC)-0.10%, adenocarcinoma in situ (AIS)-0.06% and invasive adenocarcinoma-0.01%. The increase was statistically significant for ASC (p = 0.0028), LSIL (p = 0.0069) and for HSIL (p = 0.0260). The mean ages at diagnosis of women with ASCUS, LSIL, HSIL, squamous cell carcinoma, AGC, AIS and adenocarcinoma were 37.8, 33.2, 38.6, 55.4, 41.1, 49.9 and 57.1 years, respectively. CONCLUSIONS: The increase in the rate of squamous cell abnormalities demonstrated in this study emphasizes the need of implementing an education and a screening program among Israeli women. HPV vaccine, sexual behavior, cytology performance and HPV test are primary and secondary prevention tools which may reduce morbidity and mortality in the future. In addition, based on the age at diagnosis of the different pathologies, the age group in which Pap test is performed in Israel should be expanded from 35-54 to 25-65 years.

IgG Serum Antibodies to Shigella sonnei Lipopolysaccharide Are Inversely Associated with the Incidence of Culture-Proven S. sonnei Shigellosis in Israeli Children and Adolescents.

BACKGROUND: Shigella is a leading cause of moderate-to-severe diarrhea globally, with young children most affected. The burden of shigellosis drops increasingly with age, inferring the acquisition of natural immunity. We tested the hypothesis that IgG antibodies elicited against Shigella O-specific polysaccharide (O-SP) are correlates of age-acquired immunity. OBJECTIVES: We examined levels and determinants of serum IgG to S. sonnei LPS and the association with the incidence of S. sonnei shigellosis in Israeli children and adolescents. METHODS: We analyzed 1096 serum samples from 0- to 19-year-olds collected in 2008-2015 for IgG anti-S. sonnei LPS levels by ELISA. Corresponding age-specific incidences of culture-proven S. sonnei shigellosis from 2008 to 2015 were obtained. We compared ecologically IgG levels, prevalence above a proposed protective threshold, and S. sonnei shigellosis incidence. RESULTS: In a multivariable analysis model, children aged 1-4, 5-14, and 15-19 years were 6.71, 27.68, and 48.62 times more likely to have IgG anti-S. sonnei LPS above the threshold than those aged < 1 year, respectively (p < 0.001). Infants 0-3 months old had relatively high IgG anti-S. sonnei LPS levels of maternal origin that dropped thereafter. Children of low socioeconomic status had a 2.73 times higher likelihood of having IgG anti-S. sonnei LPS above the threshold (p < 0.001). A significant inverse correlation between age-specific IgG anti-S. sonnei LPS levels and S. sonnei shigellosis incidence was observed (Spearman rho= -0.76, p = 0.028). CONCLUSIONS: The study results support anti-S. sonnei LPS antibodies as correlates of protection that can inform Shigella vaccine development.

Trends in the Epidemiology of Non-Typhoidal Salmonellosis in Israel between 2010 and 2021.

Non-typhoidal salmonellosis (NTS) is one of the most common foodborne diseases worldwide. In this study, we aimed to analyze trends in the epidemiology of NTS in the last decade in Israel. Laboratory-confirmed cases of NTS at eight sentinel laboratories were reported to the Israel Sentinel Laboratory-Based Surveillance Network, integrated with the serotype identification performed at the Salmonella National Reference Laboratory of the Ministry of Health. The decrease in NTS incidence since 1999 continued between 2010 and 2014 (16.1 per 100,000 in 2014) and was interrupted by a rise between 2015 and 2017 (39.1 per 100,000 in 2017) associated with outbreaks of Salmonella Enteritidis. The incidence of NTS dropped again thereafter (21.4 per 100,000 in 2021). The 0-4 age group was the most affected by NTS (55.5% of the cases) throughout the surveillance period. The age-adjusted incidence rates were consistently high in the summer months (June-September) and low in the winter months (December-February). The overall decrease in the incidence of NTS in Israel since 1999 was temporarily interrupted in the last decade by country-wide outbreaks involving emerging or re-emerging Salmonella serotypes. Control measures should be enhanced for all risk points of food chain transmission of Salmonella spp. to further reduce the NTS morbidity in Israel.

Estimated Infection and Vaccine Induced SARS-CoV-2 Seroprevalence in Israel among Adults, January 2020-July 2021.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) emerged in Israel in February 2020 and spread from then. In December 2020, the FDA approved an emergency use authorization of the Pfizer-BioNTech vaccine, and on 20 December, an immunization campaign began among adults in Israel. We characterized seropositivity for IgG anti-spike antibodies against SARS-CoV-2 between January 2020 and July 2021, before and after the introduction of the vaccine in Israel among adults. We tested 9520 serum samples, collected between January 2020 and July 2021. Between January and August 2020, seropositivity rates were lower than 5.0%; this rate increased from September 2020 (6.3%) to April 2021 (84.9%) and reached 79.1% in July 2021. Between January and December 2020, low socio-economic rank was an independent, significant correlate for seropositivity. Between January and July 2021, the 40.00-64.99-year-old age group, Jews and others, and residents of the Northern district were significantly more likely to be seropositive. Our findings indicate a slow, non-significant increase in the seropositivity rate to SARS-CoV-2 between January and December 2020. Following the introduction of the Pfizer-BioNTech vaccine in Israel, a significant increase in seropositivity was observed from January until April 2021, with stable rates thereafter, up to July 2021.

The Concordance between Mumps and Rubella Sero-Positivity among the Israeli Population in 2015.

Mumps and rubella are vaccine-preventable viral diseases through the measles-mumps-rubella-varicella (MMRV) vaccine, administered at 12 months and again at 6 years. We assessed the sero-prevalence of mumps and rubella, identified factors associated with sero-negativity, and evaluated concordance between mumps and rubella sero-positivity. A national cross-sectional sero-survey was conducted on samples collected in 2015 by the Israel National Sera Bank. Samples were tested for mumps and rubella IgG antibodies using an enzyme-linked immunosorbent assay. Of 3131 samples tested for mumps IgG, 84.8% (95%CI: 83.5-86.0%) were sero-positive. Sero-negativity for mumps was significantly associated with age (high odds ratios observed in infants younger than 4 years and 20-29 years old subjects). Of 3169 samples tested for rubella IgG antibodies, 95.2% (95%CI: 94.4-95.9%) were sero-positive. Rubella sero-negativity was significantly associated with age (high odds ratios observed in children younger than 4 years old and adults older than 30 years), males, Jews, and others. Concordant sero-positivity for both mumps and rubella viruses was observed in 83.9% of the tested samples. The Israeli population was sufficiently protected against rubella but not against mumps. Since both components are administered in the MMRV vaccine simultaneously, the mumps component has a lower uptake than rubella and quicker waning.

Interaction among ethnicity, socioeconomic status, and Helicobacter pylori seroprevalence in Israeli children and adolescents.

OBJECTIVES: The aim of the study was to examine the prevalence of Helicobacter pylori infection among Israeli children from different backgrounds and to assess potential interactions between ethnicity, socioeconomic status (SES), and H pylori seroprevalence. PATIENTS AND METHODS: The present sero-epidemiologic study was conducted among 0- to 20-year-old children seeking medical attention, not specifically gastrointestinal symptoms, using sera collected between 2000 and 2001 from 575 Israeli Arab children, 584 Jewish children from the general population, and sera that were obtained between 1997 and 2007 from 464 children of an ultraorthodox Jewish community. An enzyme-linked immunosorbent assay was used to measure H pylori serum immunoglobulin G antibodies and seropositivity to H pylori CagA strains. RESULTS: H pylori seropositivity was 22.9% (95% confidence interval [CI] 19.7-26.5) among Jewish children from the general population, 25.2% (95% CI 21.5-29.4) among ultraorthodox Jewish children, and 45.6% (95% CI 41.5-49.7) among Arab children. H pylori seroprevalence increased significantly with age in the 3 study groups, but it was consistently higher in Arab children. Compared with Jewish participants from high SES and controlling for age and sex, the odds ratio for H pylori seropositivity was 2.03 (95% CI 1.31-3.12) in Jewish children from intermediate SES, 2.42 (95% CI 1.29-4.53) in Arab children from intermediate SES, 2.26 (95% CI 1.52-3.36) in Jewish children from low SES, and 5.72 (95% CI 3.89-8.42) in Arab children from low SES. CagA seropositivity was 40.8% and 45.0% among Jewish and Arab children, respectively (P =0.59), and it was highest among subjects of lower SES. CONCLUSIONS: Socioeconomic factors may not totally explain the ethnic differences in H pylori prevalence.

A Significant Decrease in the Incidence of Shigellosis in Israel during COVID-19 Pandemic.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes COVID-19 and is mostly person-to-person transmitted through respiratory droplets. The implications of the strategies implemented to prevent COVID-19 transmission on other infectious diseases are unclear. We aimed to appraise trends in the incidence of salmonellosis, shigellosis and campylobacteriosis in Israel during COVID-19 pandemic. Positive stool samples for Salmonella, Shigella and Campylobacter are reported on a monthly basis to the Israel Center for Disease Control from sentinel laboratories, within the framework of a surveillance network of bacterial culture-proven enteric diseases. Age-adjusted incidence rates per 100,000 of shigellosis, salmonellosis and campylobacteriosis were calculated. Mean rates before and after the local onset of COVID-19 pandemic in Israel were compared and Relative Risk Reduction (RRR) was calculated. Joinpoint was used to evaluate secular trends. The mean age-adjusted incidence rate of shigellosis in March-July 2020 was lower than the rate observed in March-July 2018-2019 (RRR = 86.6%), but also decreased for salmonellosis (RRR = 33.0%) and campylobacteriosis (RRR = 30.0%). Using Joinpoint we have shown that the decrease observed for shigellosis was significantly sharper (Annual Percent Change (APC) = -77.7) between February 2020 and May 2020 than for salmonellosis (APC = -14.0) between July 2019 and April 2020 and for campylobacteriosis (APC = -1.1) between January 2018 and July 2020. The preventive measures applied to reduce transmission of COVID-19, including social distancing and hand washing, were ecologically associated with a decreased risk of bacterial enteric diseases in Israel. The association was strongest for shigellosis, a disease that is mostly person-to-person transmitted, as compared to salmonellosis and campylobacteriosis which are mostly foodborne transmitted.

The Israel National Sera Bank: Methods, Representativeness, and Challenges.

The Israel National Sera Bank (INSB) was established in 1997 in the Israel Center for Disease Control. The purpose of the INSB was to provide policymakers with data on the immunity status of the Israeli population against vaccine-preventable diseases, and on the extent and characteristics of exposure to emerging and re-emerging infectious diseases. The aim of this paper is to describe the methods, representativeness, and challenges in maintaining the INSB. The INSB comprises residual sera collected in six laboratories. By the end of 2019, 138,898 samples had been deposited in the INSB. These include samples from four community laboratories: 30.7% from the National Blood Service, 22.2% from Haifa and the Western Galilee, 21.7% from Soroka, and 0.7% from Jerusalem; and from two medical center laboratories: 18.6% from Schneider and 6.1% from Mayanei Hayeshua. The demographic characteristics of the sample at the end of 2019 closely resembled those of the general population. The main challenges addressed in maintaining the INSB relate to its representativeness, the possibility of repeated donors, costs, stability of antibody levels after long-term storage, ethical aspects, and the data available for each sample. The INSB is a unique, powerful, and necessary tool for assessing population immunity levels, based on serum samples collected over a long period of time.