Immunogenicity and SARS-CoV-2 Infection following the Fourth BNT162b2 Booster Dose among Health Care Workers.

INTRODUCTION: The fourth SARS-CoV-2 vaccine dose was found to protect against infection and more importantly against severe disease and death. It was also shown that the risk of symptomatic or severe disease was related to the antibody levels after vaccination or infection, with lower protection against the BA.4 BA.5 Omicron variants. The aim of our study was to assess the impact of the fourth dose on infection and perception of illness seriousness among healthcare workers (HCWs) at a tertiary health care campus in Haifa, Israel, and to investigate the possible protective effect of antibody levels against infection. METHODS: We conducted a prospective cohort study among fully vaccinated HCWs and retired employees at Rambam Healthcare Campus (RHCC), a tertiary hospital in northern Israel. Participants underwent serial serological tests at 1, 3, 6, 9, 12 and 18 months following the second BNT162b2 vaccine dose. Only a part of the participants chose to receive the fourth vaccine. A multivariable logistic regression was conducted to test the adjusted association between vaccination, and the risk of infection with SARS-CoV-2. Kaplan-Meier SARS-CoV-2 free "survival" analysis was conducted to compare the waning effect of the first and second, third and fourth vaccines. Receiver Operating Characteristic (ROC) curve was plotted for different values of the sixth serology to identify workers at risk for disease. RESULTS: Disease occurrence was more frequent among females, people age 40-50 years old and those with background chronic lung disease. The fourth vaccine was found to have better protection against infection, compared to the third vaccine; however, it also had a faster waning immunity compared to the third vaccine dose. Antibody titer of 955 AU/mL was found as a cutoff protecting from infection. CONCLUSIONS: We found that the fourth vaccine dose had a protective effect, but shorter than the third vaccine dose. Cutoff point of 955 AU/mL was recognized for protection from illness. The decision to vaccinate the population with a booster dose should consider other factors, including the spread of disease at the point, chronic comorbidities and age, especially during shortage of vaccine supply.

SARS-CoV-2 and seasonal influenza: similarities and disparities.

This report describes the differences in disease severity and clinical presentation between hospitalized patients with coronavirus disease 2019 (COVID-19) and others with seasonal influenza. A total of 136 influenza and 152 COVID-19 patients were included. Patients with influenza more frequently had dyspnea (p = 0.004), hypoxemia (p < 0.001), underlying diseases (p = 0.046), and elevated liver enzymes (p = 0.028). In contrast, patients with COVID-19 were overweight (p < 0.001), lymphopenic (p < 0.001), had elevated CRP (p = 0.011), and radiological abnormalities (p < 0.001). Patients with influenza were more severely ill on admission (NEWS > 5) (p < 0.001). However, length of hospital stay, ventilatory support, and 30-day-mortality were similar. Despite differences in clinical presentation and disease severity between influenza and COVID-19 patients, both groups had similar clinical outcomes.

Third BNT162b2 Vaccine Booster Dose against SARS-CoV-2-Induced Antibody Response among Healthcare Workers.

This study assessed humoral response to the third BNT162b2 dose among healthcare workers (HCW). This prospective cohort study of HCW tested for anti-spike antibodies (LIAISON SARS-CoV-2 S1/S2 IgG assay) at 1, 3, 6, 9, and 12 months after receiving the second BNT162b2 vaccine dose (tests 1, 2, 3, 4, and 5, respectively). A third (booster) vaccination dose was introduced before test 4. Linear regression model was used to determine the humoral response following vaccine doses. For each serology test, changes in log-transformed antibody concentrations over time, adjusted for age, sex, underlying diseases, steroid treatment, and smoking were described using the general linear mix model. Serology tests were performed at 3, 6, 9, and 12 months after the second vaccine dose in 1113, 1058, 986, and 939 participants, respectively. The third dose was received by 964 participants before the 9-month tests, 797 of whom participated in the 9- and 12-month serology tests. A significant inverse correlation was noted between time from third dose and antibody concentrations (Spearman correlation -0.395; p < 0.001). Age (p < 0.0001; CI 95% -0.005--0.004), heart disease (p < 0.0001; CI 95% -0.177--0.052), immunodeficiency (p < 0.0001; CI 95% 0.251--0.106), and smoking (p < 0.0001; CI 95% -0.122--0.040) were significantly associated with decreased antibody concentrations. Female sex (p = 0.03; CI 95% 0.013-0.066) was associated with increased antibody concentrations. The third booster dose had a better effect on immunogenicity, with higher antibody concentrations among tested HCW. Heart disease, smoking, and other known risk factors were associated with decreased antibody concentrations.

COVID-19: Healthcare Workers May Be at Greater Risk Outside Their Work Environment-A Retrospective Observational Study.

BACKGROUND: With the availability of coronavirus disease 2019 (COVID-19) vaccine, concerns have been raised regarding pre-vaccination seroprevalence in healthcare workers (HCW). This study examines the seroprevalence of HCW at an Israeli tertiary medical center before first BNT162b2 vaccination. METHODS: This was a retrospective observational study. Before vaccination, HCW at our center were offered serological testing. Data on their epidemiological, workplace, and quarantine history were collected. The SARS-CoV-2 IgG assay was performed pre-vaccination. RESULTS: A total of 4,519 (82.5%) of the HCW were tested. Of these, 210 were seropositive; 101 had no known history of COVID-19. Of the 101 asymptomatic HCW, only 3 (3%) had worked at COVID-19 departments, and 70 (69.3%) had not been previously quarantined. Positive serology was similarly distributed across age groups, and about 40% had no children. Nearly half of the HCW tested were administrative and service staff. Overall, seropositive tests were associated with having no children (OR 1.42, 95% CI 1.06-1.89; P=0.0218), history of having been quarantined without proof of disease (OR 6.04, 95% CI 4.55-8.01; P<0.001), and Arab ethnicity (OR 3.36, 95% CI 2.54-4.43; P<0.001). Seropositivity was also more prevalent in members of the administration compared to other sectors, medical and paramedical, who are exposed to patients in their daily work (OR 1.365, 95% CI 1.02-1.82; P=0.04). CONCLUSIONS: The low percentage of asymptomatic COVID-19 among our HCW may reflect the high compliance to personal protective equipment use despite treating hundreds of COVID-19 patients. The relatively high number of childless seropositive HCW could reflect misconceptions regarding children as a main source of infection, leading to carelessness regarding the need for appropriate out-of-hospital protection.

Immunogenicity trends 1 and 3 months after second BNT162B2 vaccination among healthcare workers in Israel.

OBJECTIVES: We evaluated the antibody response to the BNT162B2 vaccine among healthcare workers (HCWs) to identify factors associated with decreased immunogenicity. METHODS: This prospective cohort study included consenting HCWs who completed a questionnaire regarding background illnesses, medications, and post-vaccination allergic reactions or rash. All HCWs were tested for anti-spike antibodies (LIAISON SARS-CoV-2 S1/S2 IgG assay) 1 and 3 months after the second vaccine dose. A multivariate mixed linear model was adjusted to participants' data and fit to predict antibody levels after the second BNT162B2 vaccine dose, based on antibody levels at 1 month and the slope between 3 months and 1 month. Multivariate analyses identified factors associated with lower antibody levels. RESULTS: In total 1506 HCWs were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. Older age was associated with lower mean antibody levels (-1.22 AU/mL, p < 0.001, 95%CI -1.43 to -1.01). In addition, male sex (-22.16 AU/mL, p < 0.001, 95%CI -27.93 to -16.39), underlying condition (-10.86 AU/mL, p 0.007, 95%CI -18.81 to -2.91) and immunosuppressive treatment (-28.57 AU/mL, p 0.002, 95%CI -46.85 to -10.29) were associated with significantly lower mean antibody levels. Allergic reactions after vaccine administration or peri-vaccination glucocorticosteroid treatment were not correlated with antibody levels. CONCLUSIONS: Most HCWs had measurable antibodies at 3 months. Risk factors for lower antibody levels were older age, male sex, underlying condition, and immunosuppressive treatment. These factors may be considered when planning booster doses during vaccine shortages.

Characterization of respiratory illness surge (April-June 2021) post-COVID-19 lockdown.

INTRODUCTION: Following the opening of lockdown and relaxation of public health restrictions, an unusual surge of respiratory illness occurred during the spring/summer (Q2) 2021 season. We aimed to characterize this surge compared to previous years. METHODS: Children discharged from a single tertiary hospital for respiratory illness or selected noncommunicable diseases (NCDs) between 2015 and 2021 were included, and hospitalization rates were compared. To evaluate whether the current respiratory surge resembles a typical winter, characteristics of the second quarter (Q2, April-June) of 2021 were compared to parallel seasons and to autumn/winter (Q4, October-December) of the previous years. RESULTS: Respiratory illness showed a seasonal peak, while the pattern of NCD was consistent throughout the study period. Respiratory illnesses showed a delayed surge in Q2 2021 (389 patients), with a missing seasonal peak in Q2 and Q4 2020 (135 and 119 patients, respectively). There were more cases of croup in Q2 2021 compared to Q2 and Q4 2015-2019 (26.2 vs. 12.5% and 15.8%, p < 0.001), fewer cases of pneumonia (5.9 vs. 15.9% and 11.7%, p < 0.001), lower admission rates (22.4 vs. 36.3% and 31.5%, p < 0.001), and fewer hypoxemia during hospitalization (6.3 vs. 11.7% and 10%, p < 0.001). Additionally, lower use of antibiotics (6.2 vs. 12.3% and 10.3%, p = 0.001 and 0.012, respectively) and higher use of steroids (33.7 vs. 24.8% and 28.3%, p < 0.001 and 0.034, respectively). CONCLUSIONS: The postponed increase in respiratory morbidity after lockdown had unique characteristics, with upper respiratory illness predominating and fewer hospitalizations. Follow-up is needed to assess the altered epidemiological patterns of respiratory diseases in the post-COVID era.

Single BNT162b2 vaccine dose produces seroconversion in under 60 s cohort.

INTRODUCTION: The coronavirus disease 2019 (COVID-19) pandemic has led to worldwide vaccination development efforts. In December 2020 the Pfizer BNT162b2 vaccine was approved in the United States. This study describes the first BNT162b2 vaccine dose effect on a large cohort. METHODS: This retrospective study examined first vaccine dose effect on serology and investigated the associations between seroconversion and age or sex. RESULTS: Serological blood tests were performed on 1898 participants following first vaccine dose; 81% were tested on day 21, before receiving the second dose (mean age 47.5 ± 12.45; median 47.7, range 18-90). Positive serology was found in 92.7% of day 21 tests. Overall positivity was 86.8%, with rates increasing from 2.5% within 1-14 days to 89.8% (14-20 days), 92.7% (21 days), and 95.9% (>21 days). Mean antibody levels 21 days after first dose were 64.3 ± 33.01 AU/ml, (range 15-373 AU/ml, median 61 AU/ml). Seropositivity was greater in females than males (88.3%. vs 83.3% respectively, p < 0.001; OR1.515; 95% CI 1.152-1.994). Older age > 60 years was associated with decreased likelihood of seropositivity (p < 0.001; OR 0.926; 95% CI 0.911-0.940). Longer time between first vaccination and serology tests was associated with increased likelihood for seropositivity (p < 0.001; OR 1.350; 95% CI 1.298-1.404). CONCLUSIONS: The high seroconversion rate following first BNT162b2 dose among individuals < 60 may justify delayed delivery of the second dose, potentially help relieve the worldwide vaccination supply shortage, enable vaccination of twice this population within a shorter period, and ultimately reduce COVID-19 contagion.

Benign course and clinical features of COVID-19 in hospitalised febrile infants up to 60 days old.

AIM: Minimal data exist regarding the severity of COVID-19 in febrile infants under 60 days old. This multicentre prospective study explored the clinical course and outcomes of this hospitalised patient population, as, to date, the best approach has not been specifically addressed. METHODS: This study focused on the clinical features, laboratory parameters and outcomes of febrile infants up to 60 days old who tested positive for the virus and were hospitalised in Israel from March 2020 to January 2021. The data were extracted from a real-time prospective surveillance network for COVID-19 that includes 20 of the country's 26 hospitals. RESULTS: We identified 75 febrile young infants (60% female) with COVID-19 at a median age of 28 days (range 8-56 days). Of these, 84% had an unremarkable medical history, 29% had respiratory symptoms, and 96% had a mild illness. The Rochester criteria showed that 44% were considered at high-risk for serious bacterial infections, and we found that eight infants actually had concomitant bacterial infections. Outcomes were excellent, and no complications or fatalities were reported. CONCLUSION: The excellent outcomes of young febrile infants with COVID-19 closely resembled other respiratory viral aetiologies of fever in this age group, and there were no fatalities.

COVID-19 in a Subset of Hospitalized Children in Israel.

BACKGROUND: Most pediatric coronavirus disease 2019 (COVID-19) is mild. We assessed nationally severe COVID-19, including pediatric inflammatory multisystem syndrome (PIMS), in hospitalized children. METHODS: An ongoing, prospective, national surveillance was conducted from March 2020 through March 2021, at 20 hospitals treating children <18 years across Israel (~75% of Israeli hospitals). RESULTS: Overall, 1007 cases (439 outpatients and 568 hospitalized) identified represent 0.35% of pediatric COVID-19 nationwide (n = 291 628). Of hospitalized cases, 464 (82%), 48 (8%), and 56 (10%) had mild, moderate/severe, and PIMS disease, respectively. The mean ± SD age was 5.6 ± 6.4 years. In mild, moderate/severe, and PIMS disease, 55%, 23%, and 4% of patients were <1 year old, respectively. Obesity was reported in 1%, 4%, and 13% of patients, respectively (P < .001). The most common symptom was fever in 67%, 60%, and 100%, respectively, whereas respiratory symptoms were documented in 33%, 41%, and 38% of patients, respectively. Lymphopenia was recorded in 25%, 60%, and 86% of cases, respectively. PIMS diagnosis was mainly serology-based (in 59%). Gastrointestinal symptoms, cardiovascular involvement, rash, and conjunctivitis were noted in 82%, 61%, 57%, and 34% of PIMS episodes, respectively. Elevated C-reactive protein (100%), ferritin, troponin, D-dimer, low albumin, and thrombocytopenia were common in PIMS. Echocardiography revealed pathological findings in 33% of patients. PIMS mainstay treatment included corticosteroids (77%) and intravenous immunoglobulin (53%). No mortality was recorded. CONCLUSIONS: At a national level, pediatric COVID-19 is mild, even in hospitalized cases, with only a third presenting with respiratory involvement. PIMS is rare, but necessitates a high index of suspicion, and with suitable treatment prognosis is favorable.