Protection and Waning of Natural and Hybrid Immunity to SARS-CoV-2.

BACKGROUND: Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) provides natural immunity against reinfection. Recent studies have shown waning of the immunity provided by the BNT162b2 vaccine. The time course of natural and hybrid immunity is unknown. METHODS: Using the Israeli Ministry of Health database, we extracted data for August and September 2021, when the B.1.617.2 (delta) variant was predominant, on all persons who had been previously infected with SARS-CoV-2 or who had received coronavirus 2019 vaccine. We used Poisson regression with adjustment for confounding factors to compare the rates of infection as a function of time since the last immunity-conferring event. RESULTS: The number of cases of SARS-CoV-2 infection per 100,000 person-days at risk (adjusted rate) increased with the time that had elapsed since vaccination with BNT162b2 or since previous infection. Among unvaccinated persons who had recovered from infection, this rate increased from 10.5 among those who had been infected 4 to less than 6 months previously to 30.2 among those who had been infected 1 year or more previously. Among persons who had received a single dose of vaccine after previous infection, the adjusted rate was low (3.7) among those who had been vaccinated less than 2 months previously but increased to 11.6 among those who had been vaccinated at least 6 months previously. Among previously uninfected persons who had received two doses of vaccine, the adjusted rate increased from 21.1 among those who had been vaccinated less than 2 months previously to 88.9 among those who had been vaccinated at least 6 months previously. CONCLUSIONS: Among persons who had been previously infected with SARS-CoV-2 (regardless of whether they had received any dose of vaccine or whether they had received one dose before or after infection), protection against reinfection decreased as the time increased since the last immunity-conferring event; however, this protection was higher than that conferred after the same time had elapsed since receipt of a second dose of vaccine among previously uninfected persons. A single dose of vaccine after infection reinforced protection against reinfection.

Protection by a Fourth Dose of BNT162b2 against Omicron in Israel.

BACKGROUND: On January 2, 2022, Israel began administering a fourth dose of BNT162b2 vaccine to persons 60 years of age or older. Data are needed regarding the effect of the fourth dose on rates of confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and of severe coronavirus disease 2019 (Covid-19). METHODS: Using the Israeli Ministry of Health database, we extracted data on 1,252,331 persons who were 60 years of age or older and eligible for the fourth dose during a period in which the B.1.1.529 (omicron) variant of SARS-CoV-2 was predominant (January 10 through March 2, 2022). We estimated the rate of confirmed infection and severe Covid-19 as a function of time starting at 8 days after receipt of a fourth dose (four-dose groups) as compared with that among persons who had received only three doses (three-dose group) and among persons who had received a fourth dose 3 to 7 days earlier (internal control group). For the estimation of rates, we used quasi-Poisson regression with adjustment for age, sex, demographic group, and calendar day. RESULTS: The number of cases of severe Covid-19 per 100,000 person-days (unadjusted rate) was 1.5 in the aggregated four-dose groups, 3.9 in the three-dose group, and 4.2 in the internal control group. In the quasi-Poisson analysis, the adjusted rate of severe Covid-19 in the fourth week after receipt of the fourth dose was lower than that in the three-dose group by a factor of 3.5 (95% confidence interval [CI], 2.7 to 4.6) and was lower than that in the internal control group by a factor of 2.3 (95% CI, 1.7 to 3.3). Protection against severe illness did not wane during the 6 weeks after receipt of the fourth dose. The number of cases of confirmed infection per 100,000 person-days (unadjusted rate) was 177 in the aggregated four-dose groups, 361 in the three-dose group, and 388 in the internal control group. In the quasi-Poisson analysis, the adjusted rate of confirmed infection in the fourth week after receipt of the fourth dose was lower than that in the three-dose group by a factor of 2.0 (95% CI, 1.9 to 2.1) and was lower than that in the internal control group by a factor of 1.8 (95% CI, 1.7 to 1.9). However, this protection waned in later weeks. CONCLUSIONS: Rates of confirmed SARS-CoV-2 infection and severe Covid-19 were lower after a fourth dose of BNT162b2 vaccine than after only three doses. Protection against confirmed infection appeared short-lived, whereas protection against severe illness did not wane during the study period.

Waning Immunity after the BNT162b2 Vaccine in Israel.

BACKGROUND: In December 2020, Israel began a mass vaccination campaign against coronavirus disease 2019 (Covid-19) by administering the BNT162b2 vaccine, which led to a sharp curtailing of the outbreak. After a period with almost no cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, a resurgent Covid-19 outbreak began in mid-June 2021. Possible reasons for the resurgence were reduced vaccine effectiveness against the delta (B.1.617.2) variant and waning immunity. The extent of waning immunity of the vaccine against the delta variant in Israel is unclear. METHODS: We used data on confirmed infection and severe disease collected from an Israeli national database for the period of July 11 to 31, 2021, for all Israeli residents who had been fully vaccinated before June 2021. We used a Poisson regression model to compare rates of confirmed SARS-CoV-2 infection and severe Covid-19 among persons vaccinated during different time periods, with stratification according to age group and with adjustment for possible confounding factors. RESULTS: Among persons 60 years of age or older, the rate of infection in the July 11-31 period was higher among persons who became fully vaccinated in January 2021 (when they were first eligible) than among those fully vaccinated 2 months later, in March (rate ratio, 1.6; 95% confidence interval [CI], 1.3 to 2.0). Among persons 40 to 59 years of age, the rate ratio for infection among those fully vaccinated in February (when they were first eligible), as compared with 2 months later, in April, was 1.7 (95% CI, 1.4 to 2.1). Among persons 16 to 39 years of age, the rate ratio for infection among those fully vaccinated in March (when they were first eligible), as compared with 2 months later, in May, was 1.6 (95% CI, 1.3 to 2.0). The rate ratio for severe disease among persons fully vaccinated in the month when they were first eligible, as compared with those fully vaccinated in March, was 1.8 (95% CI, 1.1 to 2.9) among persons 60 years of age or older and 2.2 (95% CI, 0.6 to 7.7) among those 40 to 59 years of age; owing to small numbers, the rate ratio could not be calculated among persons 16 to 39 years of age. CONCLUSIONS: These findings indicate that immunity against the delta variant of SARS-CoV-2 waned in all age groups a few months after receipt of the second dose of vaccine.

Protection against Covid-19 by BNT162b2 Booster across Age Groups.

BACKGROUND: After promising initial results from the administration of a third (booster) dose of the BNT162b2 messenger RNA vaccine (Pfizer-BioNTech) to persons 60 years of age or older, the booster campaign in Israel was gradually expanded to persons in younger age groups who had received a second dose at least 5 months earlier. METHODS: We extracted data for the period from July 30 to October 10, 2021, from the Israel Ministry of Health database regarding 4,696,865 persons 16 years of age or older who had received two doses of BNT162b2 at least 5 months earlier. In the primary analysis, we compared the rates of confirmed coronavirus disease 2019 (Covid-19), severe illness, and death among those who had received a booster dose at least 12 days earlier (booster group) with the rates among those who had not received a booster (nonbooster group). In a secondary analysis, we compared the rates in the booster group with the rates among those who had received a booster 3 to 7 days earlier (early postbooster group). We used Poisson regression models to estimate rate ratios after adjusting for possible confounding factors. RESULTS: The rate of confirmed infection was lower in the booster group than in the nonbooster group by a factor of approximately 10 (range across five age groups, 9.0 to 17.2) and was lower in the booster group than in the early postbooster group by a factor of 4.9 to 10.8. The adjusted rate difference ranged from 57.0 to 89.5 infections per 100,000 person-days in the primary analysis and from 34.4 to 38.3 in the secondary analysis. The rates of severe illness in the primary and secondary analyses were lower in the booster group by a factor of 17.9 (95% confidence interval [CI], 15.1 to 21.2) and 6.5 (95% CI, 5.1 to 8.2), respectively, among those 60 years of age or older and by a factor of 21.7 (95% CI, 10.6 to 44.2) and 3.7 (95% CI, 1.3 to 10.2) among those 40 to 59 years of age. The adjusted rate difference in the primary and secondary analyses was 5.4 and 1.9 cases of severe illness per 100,000 person-days among those 60 years of age or older and 0.6 and 0.1 among those 40 to 59 years of age. Among those 60 years of age or older, mortality was lower by a factor of 14.7 (95% CI, 10.0 to 21.4) in the primary analysis and 4.9 (95% CI, 3.1 to 7.9) in the secondary analysis. The adjusted rate difference in the primary and secondary analyses was 2.1 and 0.8 deaths per 100,000 person-days. CONCLUSIONS: Across the age groups studied, rates of confirmed Covid-19 and severe illness were substantially lower among participants who received a booster dose of the BNT162b2 vaccine than among those who did not.

Protection of BNT162b2 Vaccine Booster against Covid-19 in Israel.

BACKGROUND: On July 30, 2021, the administration of a third (booster) dose of the BNT162b2 messenger RNA vaccine (Pfizer-BioNTech) was approved in Israel for persons who were 60 years of age or older and who had received a second dose of vaccine at least 5 months earlier. Data are needed regarding the effect of the booster dose on the rate of confirmed coronavirus 2019 disease (Covid-19) and the rate of severe illness. METHODS: We extracted data for the period from July 30 through August 31, 2021, from the Israeli Ministry of Health database regarding 1,137,804 persons who were 60 years of age or older and had been fully vaccinated (i.e., had received two doses of BNT162b2) at least 5 months earlier. In the primary analysis, we compared the rate of confirmed Covid-19 and the rate of severe illness between those who had received a booster injection at least 12 days earlier (booster group) and those who had not received a booster injection (nonbooster group). In a secondary analysis, we evaluated the rate of infection 4 to 6 days after the booster dose as compared with the rate at least 12 days after the booster. In all the analyses, we used Poisson regression after adjusting for possible confounding factors. RESULTS: At least 12 days after the booster dose, the rate of confirmed infection was lower in the booster group than in the nonbooster group by a factor of 11.3 (95% confidence interval [CI], 10.4 to 12.3); the rate of severe illness was lower by a factor of 19.5 (95% CI, 12.9 to 29.5). In a secondary analysis, the rate of confirmed infection at least 12 days after vaccination was lower than the rate after 4 to 6 days by a factor of 5.4 (95% CI, 4.8 to 6.1). CONCLUSIONS: In this study involving participants who were 60 years of age or older and had received two doses of the BNT162b2 vaccine at least 5 months earlier, we found that the rates of confirmed Covid-19 and severe illness were substantially lower among those who received a booster (third) dose of the BNT162b2 vaccine.

COVID-19 community care in Israel-a nationwide cohort study from a large health maintenance organization.

BACKGROUND: Among the many medical challenges presented by the COVID-19 pandemic, management of the majority of patients in community outpatient settings is crucial. The aim of this study was to describe the characteristics and outcomes among confirmed COVID-19 cases who were managed at three settings: two outpatient settings and one inpatient. METHODS: A retrospective database cohort study was conducted in a large Israeli Health Maintenance Organization. All COVID-19 cases diagnosed between 28 February 2020 and 20 July 2020 were included. Cases in the community settings were managed through a nationwide remote monitoring center, using preliminary telehealth triage and 24/7 virtual care. Outcome parameters included hospital admission, disease severity, need for respiratory support and mortality. RESULTS: About 5448 cases, aged range 0-97 years, were enrolled; 88.7% were initially managed as outpatient either at home or in designated hotels, 3.1 and 2.1% of them, respectively, later required hospitalization. The main reason for hospitalization was dyspnea; 12 were diagnosed with severe disease; 56 patients (1.3%) died, five (0.1%) of whom were initially allocated to the outpatient settings. CONCLUSIONS: Care for appropriately selected COVID-19 patients in the community provides a safe and effective option. This can contribute to reducing the hospitalization burden, with no evidence of increased morbidity or mortality.

COVID-19 in children and the effect of schools reopening on potential transmission to household members.

AIM: The effect of reopening schools on children's contribution to SARS-CoV-2 transmission, especially within households, remains controversial. This study describes the clinical presentation of a large ambulatory COVID-19 paediatric cohort and evaluates the role of children in household transmission prior to and following school reopening. METHODS: A retrospective database cohort study was conducted in a large Health Maintenance Organization in Israel. Data of all paediatric, laboratory-confirmed Coronavirus cases between 28/2/2020 and 20/6/2020 were extracted. All cases were analysed for household contacts and primary cases within each family cluster. RESULTS: A total of 1,032 cases under 18 years old (median age 12 years) were included. Of these cases, 432 (41.9%) were asymptomatic; 122 (11.8%) cases acquired the infection at school, and 45 of them were part of two school clusters; 846 children had at least one positive household contact, in 498 family clusters, and among them, 293 primary cases were identified. Only 27 (9.2%) primary cases were under 18 years of age and six (2%) were below 10. The proportion of primary cases did not change after the re-opening of educational facilities. CONCLUSION: Children, particularly under 10 years of age, are less likely to be the vector for SARS-CoV-2 infection within household settings. Opening educational facilities did not change transmission dynamics.

[OUTSOURCING OF MEDICAL SERVICES FOR SOLDIERS TO CIVILIAN HEALTH FUNDS].

INTRODUCTION: The Israeli Medical Corps provides a great deal of medical services by its own medical personnel and purchases some services from various civilian suppliers, including public hospitals. Although the IDF has bought hospital services since it's early days, few attempts have been made to purchase primary and secondary medical services for soldiers in rear units. This article presents an analysis of the outsourcing project ("Aviv" project) of medical services for rear units which was operating between the years 2010 - 2014. In this project soldiers chose to receive services from one of the four healthcare funds in Israel. The project is analyzed from two perspectives, military and civilian, based on the personal experience of the author who led the implementation of the project while he was the Surgeon General of the Medical Corps and gained additional experience at a later stage during his positions in Maccabi Healthcare Services. Despite the different policies of the medical corps and the healthcare funds that are described in the article, it is advisable to utilize the civilian infrastructure in Israel to provide soldiers with better medical services. Future projects should consider the lessons learned from the Aviv project and adjust the demands of the Medical Corps from the healthcare funds, so that soldiers will receive similar services to their civilian counterparts. Among other recommendations, the author advises that soldiers will pay copayment and will receive broad services, including the basic basket and complimentary health services.

[TELENEUROLOGY CLINIC - HIGH COMPLIANCE AND ADHERENCE].

BACKGROUND: Telemedicine carries the potential of providing healthcare for individuals with limited access to clinics. While in some subspecialties telemedicine has been proved to be effective, its efficacy for replacing standard visits in complex subspecialties, such as pediatric neurology, has not been studied. OBJECTIVES: To determine compliance and adherence to follow-up and medication prescription for online pediatric neurology clinics. METHODS: We reviewed clinical records for follow-up and prescription requests of medication prescribed for children visiting the Maccabi Online Neuropediatric clinic in Ariel. RESULTS: A total of 78 children (aged 10.9±3.2 years; 40 girls, 38 boys) visited the online neuropediatric clinic between October 2015 and November 2017; 78 first visits, 44 follow-up visits. The first visit lasted 50 minutes including technical time. The main diagnoses were ADD/ADHD (41/78, 53%), followed by behavioral/emotional issues (11/78, 14%), headaches/migraines (9/78, 12%), learning disabilities (8/78, 10%) epilepsy (4/78, 5%) and others (5/78, 6%). Follow-up was recommended in most cases (48/78, 62%) mainly for ADD/ADHD and headaches/migraines. Most patients complied with follow-up (55%) with better rates among ADD/ADHD (19/29, 66%). Only a few patients (3/78,4%) continued follow-up in a regular clinic. Medication was recommended for 29/41 (71%) children with ADD/ADHD; all of whom requested medication prescription from the pediatrician (as it could not be prescribed digitally). Adherence was high as most patients (24/29, 83%) continued to request medication prescription. CONCLUSIONS: While adherence and compliance rates are high in tele-neurology clinics, especially for ADHD, further controlled studies are needed to compare services to regular visits and to assess the additional benefits of specialists healthcare delivery to underserved populations.

Blood glucose levels as an adjunct for prehospital field triage.

OBJECTIVE: Elevated blood glucose levels (BGL) are known to be part of the physiologic response to stress following physical trauma. We aimed to study whether a measured BGL might help improve accuracy of field triage. METHODS: We conducted a retrospective study using the Israel Defense Forces Trauma Registry. BGLs were determined upon hospital arrival and were not available to medical providers in the field. RESULTS: There were 706 casualties in the registry who had a recorded BGL upon hospital arrival. Sixty percent (18/30) of casualties who had a BGL ≥200 mg/dL had been triaged in the field as severely wounded, whereas 11% (71/651) of casualties who had a BGL <200 mg/dL had been triaged as severely wounded. For predicting an Injury Severity Score >15, the positive likelihood ratio using field triage of severe was 11, using BGL ≥200 mg/dL was 8, and using a combination of the two tests was 26. For predicting the need for intensive care unit (ICU) admission, the ratios were 8, 13, and 23, respectively. CONCLUSIONS: Elevated BGL improved prediction of high Injury Severity Score and ICU use among casualties triaged as severe. If future research using BGL measured in the field yields similar results, combining BGL with standard field triage may allow for more accurate identification of casualties who need acute field intervention, have major injury, or require ICU admission.

[Health Information Technology -where are we heading?].

The current issue of "Harefuah" dedicates a special corner to Health Information Technology (HIT), with a collection of five review papers discussing different areas of the field, focusing on its benefits to the quality of healthcare. In the first paper Topaz and Ash describe the United States MeaningfuL Use project, and list the lessons that the Israeli health system should learn from it. Zelingher and Ash analyze the decision of the Israeli Ministry of Health to move from the old coding system of ICD-9-CM to a combination of SNOMED-CT as a clinical terminology system and ICD-10-CM as the classification coding system. The authors conclude that achieving a standardized, homogenous and thorough coding of problems, diagnoses and procedures will enable interoperability in the Israeli health system. Shalom et al present us to the world of computerized clinical guidelines. They review the different projects that aim to bring tools and methods to transform the paper based guidelines to computer programs that support the everyday decisions that physicians take regarding their patients. The authors focus on their experience in developing methodology, tools and a library of computerized guidelines, and describe their evaluation in several projects. Shahar et al dive deeper to describe the challenge of representing time in cLinicaL guidelines and creating tools to discover new knowledge based on represented known knowledge. These two papers demonstrate the meaningful use of medicaL data. In the last article, Siegal addresses some legal concerns evolving from the HIT revolution, pointing to the emerging concepts in Israeli jurisprudence, which regards medical IT as an important contribution to patient empowerment, aspects of medical risk management and management of national health system resources. In the judgment of the Israeli court, a medical organization will possibly have to take the responsibiLity of not implementing a proven HIT system. This paper concludes with descriptions of two studies evaluating health information systems in Israel. These studies will be presented at the forthcoming conference of the IsraeLi Association of Medical Informatics (ILAMI).

[Overview of the US policies for health information technology and lessons learned for Israel].

The heaLthcare system in the United States (U.S.) faces a number of significant changes aimed at improving the quality and availability of medical services and reducing costs. Implementation of health information technologies, especiaLly ELectronic Health Records (EHR), is central to achieving these goals. Several recent Legislative efforts in the U.S. aim at defining standards and promoting wide scale "Meaningful Use" of the novel technologies. In Israel, the majority of heaLthcare providers adopted EHR throughout the Last decade. Unlike the U.S., the process of EHR adoption occurred spontaneously, without governmental control or the definition of standards. In this article, we review the U.S. health information technology policies and standards and suggest potential lessons Learned for Israel. First, we present the three-staged Meaningful Use regulations that require eligible healthcare practitioners to use EHR in their practice. We also describe the standards for EHR certification and national efforts to create interoperable health information technology networks. Finally, we provide a brief overview of the IsraeLi regulation in the field of EHR. Although the adoption of health information technology is wider in Israel, the Lack of technology standards and governmental control has Led to Large technology gaps between providers. The example of the U.S. Legislation urges the adoption of several critical steps to further enhance the quality and efficiency of the Israeli healthcare system, in particular: strengthening health information technology regulation; developing Licensure criteria for health information technology; bridging the digital gap between healthcare organizations; defining quality measures; and improving the accessibility of health information for patients.

[Data coding in the Israeli healthcare system - do choices provide the answers to our system's needs?].

The IsraeLi healthcare system has undergone major processes for the adoption of health information technologies (HIT), and enjoys high Levels of utilization in hospital and ambulatory care. Coding is an essential infrastructure component of HIT, and ts purpose is to represent data in a simplified and common format, enhancing its manipulation by digital systems. Proper coding of data enables efficient identification, storage, retrieval and communication of data. UtiLization of uniform coding systems by different organizations enables data interoperability between them, facilitating communication and integrating data elements originating in different information systems from various organizations. Current needs in Israel for heaLth data coding include recording and reporting of diagnoses for hospitalized patients, outpatients and visitors of the Emergency Department, coding of procedures and operations, coding of pathology findings, reporting of discharge diagnoses and causes of death, billing codes, organizational data warehouses and national registries. New national projects for cLinicaL data integration, obligatory reporting of quality indicators and new Ministry of Health (MOH) requirements for HIT necessitate a high Level of interoperability that can be achieved only through the adoption of uniform coding. Additional pressures were introduced by the USA decision to stop the maintenance of the ICD-9-CM codes that are also used by Israeli healthcare, and the adoption of ICD-10-C and ICD-10-PCS as the main coding system for billing purpose. The USA has also mandated utilization of SNOMED-CT as the coding terminology for the ELectronic Health Record problem list, and for reporting quality indicators to the CMS. Hence, the Israeli MOH has recently decided that discharge diagnoses will be reported using ICD-10-CM codes, and SNOMED-CT will be used to code the cLinical information in the EHR. We reviewed the characteristics, strengths and weaknesses of these two coding systems. In summary, the adoption of ICD-10-CM is in line with the USA decision to abandon ICD-9-CM, and the Israeli heaLthcare system could benefit from USA heaLthcare efforts in this direction. The Large content of SNOMED-CT and its sophisticated hierarchical data structure will enable advanced cLinicaL decision support and quality improvement applications.

The COVID-19 pandemic posed many dilemmas for policymakers, which sometimes resulted in unprecedented decision-making.

BACKGROUND: The COVID-19 pandemic evolved through five phases, beginning with 'the great threat', then moving through 'the emergence of variants', 'vaccines euphoria', and 'the disillusionment', and culminating in 'a disease we can live with'. Each phase required a different governance response. With the progress of the pandemic, data were collected, evidence was created, and health technology was developed and disseminated. Policymaking shifted from protecting the population by limiting infections with non-pharmaceutical interventions to controlling the pandemic by prevention of severe disease with vaccines and drugs for those infected. Once the vaccine became available, the state started devolving the responsibility for the individual's health and behavior. MAIN BODY: Each phase of the pandemic posed new and unique dilemmas for policymakers, which resulted in unprecedented decision-making. Restrictions to individual's rights such as a lockdown or the 'Green Pass policy' were unimaginable before the pandemic. One of the most striking decisions that the Ministry of Health made was approving the third (booster) vaccine dose in Israel, before it was approved by the FDA or any other country. It was possible to make an informed, evidence-based decision due to the availability of reliable and timely data. Transparent communication with the public probably promoted adherence to the booster dose recommendation. The boosters made an important contribution to public health, even though their uptake was less than the uptake for the initial doses. The decision to approve the booster illustrates seven key lessons from the pandemic: health technology is key; leadership is crucial (both political and professional); a single body should coordinate the actions of all stakeholders involved in the response, and these should collaborate closely; policymakers need to engage the public and win their trust and compliance; data are essential to build a suitable response; and nations and international organizations should collaborate in preparing for and responding to pandemics, because viruses travel without borders. CONCLUSION: The COVID-19 pandemic posed many dilemmas for policymakers. The lessons learned from the actions taken to deal with them should be incorporated into preparedness for future challenges.

Initial protection against SARS-CoV-2 omicron lineage infection in children and adolescents by BNT162b2 in Israel: an observational study.

BACKGROUND: The BNT162b2 (Pfizer-BioNTech) two-dose vaccine regiment for children and the BNT162b2 third dose for adolescents were approved shortly before the SARS-CoV-2 omicron (B.1.1.529) outbreak in Israel. We aimed to estimate the effects of these vaccines on the rates of confirmed infection against the omicron variant in children and adolescents. METHODS: In this observational cohort study, we extracted data for the omicron-dominated (sublineage BA.1) period. We compared rates of confirmed SARS-CoV-2 infection between children aged 5-10 years 14-35 days after receiving the second vaccine dose with an internal control group of children 3-7 days after receiving the first dose (when the vaccine is not yet effective). Similarly, we compared confirmed infection rates in adolescents aged 12-15 years 14-60 days after receiving a booster dose with an internal control group of adolescents 3-7 days after receiving the booster dose. We used Poisson regression, adjusting for age, sex, socioeconomic status, calendar week, and exposure. FINDINGS: Between Dec 26, 2021, and Jan 8, 2022, we included 1 158 289 participants. In children aged 5-10 years, the adjusted rate of confirmed infection was 2·3 times (95% CI 2·0-2·5) lower in children who received a second dose than in the internal control group. The adjusted infection rate in children who received a second dose was 102 infections per 100 000 risk-days (94-110) compared with 231 infections per 100 000 risk-days (215-248) in the corresponding internal control cohort. In adolescents aged 12-15 years, the booster dose decreased confirmed infection rates by 3·3 times (2·8-4·0) compared with in the internal control group. The adjusted infection rate of the booster cohort was 70 per 100 000 risk-days (60-81) compared with 232 per 100 000 risk-days (212-254) in the internal control cohort. INTERPRETATION: A recent two-dose vaccination regimen with BNT162b2 and a recent booster dose in adolescents substantially reduced the rate of confirmed infection compared with the internal control groups. Future studies are needed to assess the duration of this protection and protection against other outcomes such as paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 and long-COVID. FUNDING: None.

Protection against Omicron BA.1/BA.2 severe disease 0-7 months after BNT162b2 booster.

Following evidence of waning immunity against both infection and severe disease after 2 doses of the BNT162b2 vaccine, Israel began administering a 3rd BNT162b2 dose (booster) in July 2021. Recent studies showed that the 3rd dose provides a much lower protection against infection with the Omicron variant compared to the Delta variant and that this protection wanes quickly. However, there is little evidence regarding the protection of the 3rd dose against Omicron (BA.1/BA.2) severe disease. In this study, we estimate the preservation of immunity from severe disease up to 7 months after receiving the booster dose. We calculate rates of severe SARS-CoV-2 disease between groups of individuals aged 60 and above, comparing those who received two doses at least 4 months previously to those who received the 3rd dose (stratified by the time from vaccination), and to those who received a 4th dose. The analysis shows that protection conferred by the 3rd dose against Omicron severe disease did not wane over a 7-month period. Moreover, a 4th dose further improved protection, with a severe disease rate approximately 3-fold lower than in the 3-dose cohorts.

Analysis of the causes of death of casualties in field military setting.

OBJECTIVE: We assessed the causes of death of military casualties in order to determine the characteristics of injury and to determine how survivability can be improved. METHODS: A retrospective review of the trauma registry of the Israel Defense Forces was conducted. The causes of death were determined. Casualties that were found alive but died later at any level of care were included. RESULTS: Information about casualties that was recorded during the years 2002-2009 was reviewed. Eighty-one fatalities were included in the analysis. Fifty-one (63%) fatalities were caused by gunshot wounds. Analysis of the data regarding the cause of death revealed that 66 (81.5%) of the casualties died because of hemorrhage and 25 (30.9%) because of head trauma. Of the casualties that died of hemorrhage, 12 (18.2%) had neck or limbs potentially compressible hemorrhage. All fatalities from hemorrhage died before arriving at a medical facility. CONCLUSION: Torso noncompressible hemorrhage was found to be the main cause of death among the casualties investigated. Potentially compressible hemorrhage and head injury are significant too. Research and development of means to treat hemorrhage and emphasis on distribution of means to stop hemorrhage and on training may improve outcome of potentially compressible hemorrhage.

Training modalities and self-confidence building in performance of life-saving procedures.

OBJECTIVE: Physicians and paramedics in the Israel Defense Forces are trained to perform advanced medical procedures using standardized training modalities, such as manikins. We studied the association of experience using these training modalities with self-reported confidence in procedure performance. METHODS: Providers were sent a questionnaire regarding their experience with and self-confidence levels for performing endotracheal intubation, cricothyroidotomy, needle chest decompression, tube thoracostomy, and intraosseous infusion. RESULTS: Provider level (physician or paramedic) and gender were associated with reported self-confidence levels. Manikin and supervised and unsupervised patient experience exhibited positive associations with self-confidence, but (animal) model experience did not. For many procedure-training modality pairs, we identified a plateau level above which additional experience was minimally associated with an increase in self-confidence. CONCLUSIONS: Among military advanced life support providers, self-confidence levels in procedure performance are positively associated with experience gained from manikins and supervised and unsupervised patient application. We were not able to demonstrate a clear benefit of an animal model in increasing self-confidence. A plateau was generally identified, indicating decreased benefit from the use of a particular training modality for a particular procedure. Modifying training regimens in light of these findings may help maximize the self-confidence of advanced life support providers more efficiently.