Risk Stratification Model for Severe COVID-19 Disease: A Retrospective Cohort Study.

BACKGROUND: Risk stratification models have been developed to identify patients that are at a higher risk of COVID-19 infection and severe illness. Objectives To develop and implement a scoring tool to identify COVID-19 patients that are at risk for severe illness during the Omicron wave. METHODS: This is a retrospective cohort study that was conducted in Israel's second-largest healthcare maintenance organization. All patients with a new episode of COVID-19 between 26 November 2021 and 18 January 2022 were included. A model was developed to predict severe illness (COVID-19-related hospitalization or death) based on one-third of the study population (the train group). The model was then applied to the remaining two-thirds of the study population (the test group). Risk score sensitivity, specificity, and positive predictive value rates, and receiver operating characteristics (ROC) were calculated to describe the performance of the model. RESULTS: A total of 409,693 patients were diagnosed with COVID-19 over the two-month study period, of which 0.4% had severe illness. Factors that were associated with severe disease were age (age > 75, OR-70.4, 95% confidence interval [CI] 42.8-115.9), immunosuppression (OR-4.8, 95% CI 3.4-6.7), and pregnancy (5 months or more, OR-82.9, 95% CI 53-129.6). Factors that were associated with a reduced risk for severe disease were vaccination status (patients vaccinated in the previous six months OR-0.6, 95% CI 0.4-0.8) and a prior episode of COVID-19 (OR-0.3, 95% CI 0.2-0.5). According to the model, patients who were in the 10th percentile of the risk severity score were considered at an increased risk for severe disease. The model accuracy was 88.7%. CONCLUSIONS: This model has allowed us to prioritize patients requiring closer follow-up by their physicians and outreach services, as well as identify those that are most likely to benefit from anti-viral treatment during the fifth wave of infection in Israel, dominated by the Omicron variant.

Association Between AZD7442 (Tixagevimab-Cilgavimab) Administration and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection, Hospitalization, and Mortality.

BACKGROUND: Intramuscular AZD7442 (Tixagevimab-Cilgavimab, (Evusheld)) has been found effective among immunocompromised individuals (ICI) in reducing Sars-Cov-2 infection and severe disease in ICIs. We evaluated the association between AZD7442 administration and SARS-CoV-2 infection and severe disease (COVID-19 hospitalization and all-cause mortality) among selected ICIs, during a fifth Omicron-dominated wave of COVID-19 (Dec 2021-April 2022) in Israel. METHODS: ICIs aged 12 and over identified in the Maccabi HealthCare Services database were invited by SMS/email to receive AZD7442. Demographic information, comorbidities, coronavirus vaccination and prior SARS-CoV-2 infection and COVID-19 outcome data (infection, severe disease), were extracted from the database. Rates of infection and severe disease were compared between those administered AZD7442 and those who did not respond to the invitation, over a three-month period. RESULTS: Of all 825 ICIs administered AZD7442, 29 (3.5%) became infected with SARS-CoV-2 compared to 308 (7.2%) of 4299 ICIs not administered AZD7442 (p < 0.001). After adjustment, the AZD7442 group were half as less likely to become infected with Sars-Cov-2 than the non-administered group (OR: 0.51, 95% CI: 0.30-0.84). One person in the AZD7442 group (0.1%) was hospitalized for COVID-19 compared to 27 (0.6%) in the non-administered group (p = 0.07). No mortality was recorded among the AZD7442 group, compared to 40 deaths (0.9%) in the non-administered group (p = 0.005). After adjustment, ICIs administered AZD7442 were 92% less likely to be hospitalized/die than those not administered AZD7442 (OR: 0.08, 95% CI: 0.01-0.54). CONCLUSIONS: AZD7442 among ICI may protect against Omicron variant infection and severe disease, and should be considered for pre-exposure prophylactic AZD7442.

Immediate side effects of Comirnaty COVID-19 vaccine: A nationwide survey of vaccinated people in Israel, December 2020 to March 2021.

BackgroundCOVID-19 vaccine safety is of major interest worldwide, since there is no prior experience with it. Israel was one of the first countries to widely use the Comirnaty vaccine.AimWe aimed to assess the vaccine's short-term side effects directly from a large population and to predict influencing factors for self-reporting side effects.MethodsIn a retrospective cohort study, we investigated self-reported systemic vaccine side-effects using electronic surveys sent to vaccinated individuals between 20 December 2020 and 11 March 2021, within 3 days following administration of the first and second dose. We determined predictors for reporting systemic side effects by logistic regression.ResultsA total of 1,213,693 patients received at least one vaccine dose and 301,537 (24.8%) answered at least one survey. Among them, 68,162 (30.4%) and 89,854 (59.9%) individuals filled the first and the second dose surveys, respectively, and reported one or more side effects. Most common side effects were fatigue, headache and myalgia. Several respondents reported facial paraesthesia after first and second dose, respectively (n = 1,675; 0.7% and n = 1,601; 1.1%). Individuals younger than 40 years and women reported side effects more frequently than others, but pregnant women reported less. Pregnancy was a weak predictor for reporting any side effect in general and in particular fatigue, myalgia, headache, chills and fever.ConclusionsWe found further support for minor short-term side effects, within 3 days of receiving the Comirnaty vaccine. These findings from vaccine recipients in general and pregnant women in particular can improve vaccine acceptance.

Pfizer-BioNTech vaccine effectiveness against Sars-Cov-2 infection: Findings from a large observational study in Israel.

Development of an effective vaccine against Covid-19 is crucial to reducing infection. mRNA BNT162b2, developed and manufactured by Pfizer-BioNTech, was one of the first FDA-approved vaccinations reporting high efficacy (95%) and minimal side effects. Evaluating effectiveness of BNT162b2 in a general population has been made possible after the implementation of a nation-wide vaccination program in Israel. This retrospective cohort study was carried out in Maccabi HealthCare services, Israel among 1.6 million members aged 16 and over. The population was divided into those who were at least seven days post- second vaccination and those who had not been vaccinated. Number of days till the end of the study or Covid-19 infection, Covid-19-related hospitalization and mortality was calculated for each participant between 18.1.2021 to 25.4.2021. Participants who had reached day eight after second vaccination during the study period could contribute days to both groups. Vaccine efficacy (VE) was calculated using a conditional Poisson model, controlling for age group, gender, hypertension, diabetes and obesity, fitted within clusters defined by geographical statistical area and calendar week. BNT162b2 was found effective for the total population group for infection, hospitalization and mortality, with adjusted VE of 93·0% (CI:92·6-93·4%), 93·4% (CI:91·9-94·7%) and 91·1% (CI:86·5-94·1%) respectively. VE for infection was lower for participants aged 75 and over, and for those with hypertension, diabetes and obesity. This study strengthens the evidence that the Pfizer-BioNTech vaccination is effective in preventing infection, hospitalization and mortality.

Effectiveness of a Third Dose of BNT162b2 mRNA Vaccine.

A retrospective cohort study was carried out in a large Israeli health maintenance organization to determine vaccine effectiveness (VE) of a third dose of BNT162b2 vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Of nearly 1 million members receiving 2 doses of BNT162b2 in January-February 2021, infection rates (based on polymerase chain reaction results) were compared between those who received a third dose with those who did not during August-October 2021 (maximum, 70 days). Crude VE was 92.9% (95% confidence interval [CI], 92.6%-93.2%) and adjusted VE was 89.1% (95% CI, 87.5%-90.5%). We conclude that the third dose provides added protection against SARS-CoV-2 infection for those vaccinated 6 months ago.

Reactogenicity of a third BNT162b2 mRNA COVID-19 vaccine among immunocompromised individuals and seniors - A nationwide survey.

BACKGROUND: Since July 13, 2021, a third SARS-CoV-2 vaccine BNT162b2 was approved in Israel to immunocompromised and seniors 60 years of age or older. We aimed to evaluate vaccine's reactogenicity. METHODS: A retrospective cohort, using electronic surveys sent to booster vaccine recipients, during July 20-August 10, 2021. RESULTS: 17,820 participated in the survey, with a response rate of 30.2%. 3195 (17.9%) were immunocompromised. Fatigue, myalgia and fever were the most frequent systemic side effects reported (19.6%, 9.2% and 8.1% respectively among immunocompromised; 21.3%, 9.9% and 9.2% respectively among seniors). 67.3% of immunocompromised and 62% of seniors reported experiencing a better or a similar response to the third dose, compared to the second. CONCLUSIONS: Local and systemic reactions after third BNT162b2 vaccine, reported by immunocompromised and seniors, were similar to those observed following previous vaccines and mostly self-resolved. These findings may aid promoting confidence among vaccine providers and recipients.

Longitudinal symptom dynamics of COVID-19 infection.

As the COVID-19 pandemic progresses, obtaining information on symptoms dynamics is of essence. Here, we extracted data from primary-care electronic health records and nationwide distributed surveys to assess the longitudinal dynamics of symptoms prior to and throughout SARS-CoV-2 infection. Information was available for 206,377 individuals, including 2471 positive cases. The two datasources were discordant, with survey data capturing most of the symptoms more sensitively. The most prevalent symptoms included fever, cough and fatigue. Loss of taste and smell 3 weeks prior to testing, either self-reported or recorded by physicians, were the most discriminative symptoms for COVID-19. Additional discriminative symptoms included self-reported headache and fatigue and a documentation of syncope, rhinorrhea and fever. Children had a significantly shorter disease duration. Several symptoms were reported weeks after recovery. By a unique integration of two datasources, our study shed light on the longitudinal course of symptoms experienced by cases in primary care.