Nationwide seroprevalence of antibodies against SARS-CoV-2 in Israel.

The first local spread of COVID-19 in Israel was detected in March 2020. Due to the diversity in clinical presentations of COVID-19, diagnosis by RT-PCR alone might miss patients with mild or no symptoms. Serology testing may better evaluate the actual magnitude of the spread of infection in the population. This is the first nationwide seroprevalence study conducted in Israel. It is one of the most widespread to be conducted thus far, and the largest per-country population size. The survey was conducted between June 28 and September 14, 2020 and included 54,357 patients who arrived at the Health Maintenance Organizations to undergo a blood test for any reason. A patient was considered seropositive after two consecutive positive results with two different kits (Abbott and DiaSorin).The overall seroprevalence was 3.8% (95%CI 3.7-4.0), males higher than females [4.9% (95%CI 4.6-5.2) vs. 3.1% (95%CI 2.9-3.3) respectively]. Adolescents had the highest prevalence [7.8% (95%CI 7.0-8.6)] compared to other age groups. Participants who had undergone RT-PCR testing had a tenfold higher risk to be seropositive. The prevalence-to-incidence ratio was 4.5-15.7. Serology testing is an important complimentary tool for assessing the actual magnitude of infection and thus essential for implementing policy measures to control the pandemic. A positive serology test result was recently accepted in Israel as being sufficient to define recovery, with possible far-reaching consequences, such as the deploying of employees to ensure the maintenance of a functional economy.

Clinical and Laboratory Features in the Israeli Population with COVID-19 Infection after Pfizer-BioNTech mRNA Booster Vaccination.

Background: Immune protection following either vaccination or infection with SARS-CoV-2 decreases over time. Objective: We aim to describe clinical and sociodemographic characteristics associated with COVID-19 infection at least 14 days after booster vaccination in the Israeli population. Methods: We conducted a population-based study among adult members of Leumit Health Services (LHS) in Israel. Nasopharyngeal swabs were examined for SARS-CoV-2 by real-time RT-PCR. The hematological and biochemical parameters in the peripheral blood before booster vaccination were evaluated. Results: Between 1 February 2021 and 30 November 2021, 136,683 individuals in LHS were vaccinated with a booster (third dose) of the BNT162b2 vaccine. Of these, 1171 (0.9%) were diagnosed with COVID-19 by testing positive for SARS-CoV-2 RT-PCR at least >14 days after the booster vaccination. The COVID-19-positive group was characterized by higher rates of chronic kidney disease than the matched COVID-19-negative group (43 (3.7%) vs. 3646 (2.7%); p = 0.039). Anemia, lower peripheral blood lymphocytes, monocytes, basophils, C3 Complement, cholesterol, and prothrombin time were also associated with COVID-19 after booster vaccination. Conclusion: People with chronic kidney disease and anemia should be included in possible future annual SARS-CoV-2 vaccination recommendations.

Absence of APOL1 risk variants protects against HIV-associated nephropathy in the Ethiopian population.

BACKGROUND: Susceptibility to end-stage kidney disease (ESKD) among HIV-infected Americans of African ancestral heritage has been attributed to APOL1 genetic variation. We determined the frequency of the APOL1 G1 and G2 risk variants together with the prevalence of HIV-associated nephropathy (HIVAN) among individuals of Ethiopian ancestry to determine whether the kidney disease genetic risk is PanAfrican or restricted to West Africa, and can explain the previously reported low risk of HIVAN among Ethiopians. METHODS: We studied a cohort of 338 HIV-infected individuals of Ethiopian ancestry treated in one Israeli and one Ethiopian center. We sought clinical evidence for HIVAN (serum creatinine >1.4 mg/dl or proteinuria >30 mg/dl in a spot urine sample). Genetic analyses included the genotyping of the APOL1 G1 and G2 variants, and a panel of 33 genomic ancestry-informative markers. Statistical analysis compared clinical and genetic indices for HIV-infected individuals of Ethiopian ancestry and overall Ethiopians to those reported for HIV-infected African-Americans, overall African-Americans, West Africans and non-Africans. FINDINGS: Three (0.8%) of 338 HIV-infected patients of Ethiopian ancestry showed clinical criteria compatible with renal impairment. Two of these 3 patients also have severe poorly controlled diabetes mellitus. The third nondiabetic patient underwent renal biopsy which ruled out HIVAN. This absence of clinically apparent HIVAN was significantly different from that reported for African-Americans. The APOL1 G1 and G2 risk variants were found, respectively, in 0 and 2 (heterozygote state) of the 338 HIV-infected individuals. Global ancestry and the frequencies of the APOL1 G1 and G2 variants are not statistically different from their frequencies in the general Ethiopian population, but are significantly and dramatically lower than those observed among HIV-infected African-Americans, African-Americans and West Africans. INTERPRETATION: The coinciding absence of HIVAN and the APOL1 risk variants among HIV-infected individuals of Ethiopian ancestry support a Western rather than Pan-African ancestry risk for ESKD, and can readily explain the lack of HIVAN among individuals of Ethiopian ancestry.

The effect of surface treatments on the adhesion of electrochemically deposited hydroxyapatite coating to titanium and on its interaction with cells and bacteria.

The effect of different mechanical and chemical pre-treatments on the adhesion strength of hydroxyapatite (HAp) coating on a commercially pure titanium (CP-Ti) substrate was studied by means of a standard tensile test followed by microscopic and chemical analysis to determine the locus of fracture. In addition, the effects of either these pre-treatments or post-treatment by low-energy electron irradiation, which allowed tuning the wettability of the surface, on both osteoblast progenitor attachment and S. aureus bacteria attachment were investigated. A dedicated program was developed for unambiguous identification and count of stained cells. A single-phase HAp coating was formed by electrodeposition. A series of surface pre-treatments consisted of grinding down to P1000, etching in HNO3/HF solution, grit blast, soaking in NaOH and subsequent heat treatment provided the highest adhesion strength to the HAp coating. Osteoblast progenitors derived from rats may be attached preferentially to a hydrophilic surface (post-treatment to θ = 30°), while the bacteria seemed to be less attached to hydrophobic surfaces (post-treatment to θ = 105°). However, the results were not statistically different. The bacteria seemed to be less attached to the smoother, uncoated surfaces.

Large-scale study of antibody titer decay following BNT162b2 mRNA vaccine or SARS-CoV-2 infection.

BACKGROUND: Immune protection following either vaccination or infection with SARS-CoV-2 decreases over time. OBJECTIVE: To determine the kinetics of SARS-CoV-2 IgG antibodies following administration of two doses of BNT162b2 vaccine, or SARS-CoV-2 infection in unvaccinated individuals. METHODS: Antibody titers were measured between January 31, 2021, and July 31, 2021 in two mutually exclusive groups: i) vaccinated individuals who received two doses of BNT162b2 vaccine and had no history of previous infection with COVID-19 and ii) SARS-CoV-2 convalescents who had not received the vaccine. RESULTS: A total of 2,653 individuals fully vaccinated by two doses of vaccine during the study period and 4,361 convalescent patients were included. Higher SARS-CoV-2 IgG antibody titers were observed in vaccinated individuals (median 1581 AU/mL IQR [533.8-5644.6]) after the second vaccination, than in convalescent individuals (median 355.3 AU/mL IQR [141.2-998.7]; p<0.001). In vaccinated subjects, antibody titers decreased by up to 40% each subsequent month while in convalescents they decreased by less than 5% per month. Six months after BNT162b2 vaccination 16.1% subjects had antibody levels below the seropositivity threshold of <50 AU/mL, while only 10.8% of convalescent patients were below <50 AU/mL threshold after 9 months from SARS-CoV-2 infection. CONCLUSIONS: This study demonstrates individuals who received the Pfizer-BioNTech mRNA vaccine have different kinetics of antibody levels compared to patients who had been infected with the SARS-CoV-2 virus, with higher initial levels but a much faster exponential decrease in the first group. FUNDING: This research was internally funded by Leumit Health Services (LHS) and was supported in part by the Intramural Research Program, National Institutes of Health, National Cancer Institute, Center for Cancer Research.The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government. IMPACT STATEMENT: Large scale study display the kinetics of SARS-CoV-2 IgG antibodies present in individuals vaccinated with two doses of mRNA vaccine vs. unvaccinated patients who had recovered from the disease: initial levels of antibody are much higher in vaccinated patients, but decrease faster.

Elapsed time since BNT162b2 vaccine and risk of SARS-CoV-2 infection: test negative design study.

OBJECTIVES: To determine whether time elapsed since the second injection of the Pfizer-BioNTech BNT162b2 mRNA vaccine was significantly associated with the risk of covid-19 infection after vaccination in people who received two vaccine injections. DESIGN: Test negative design study. SETTING: Electronic health records of a large state mandated healthcare organisation, Israel. PARTICIPANTS: Adults aged ≥18 years who had received a reverse transcription polymerase chain reaction (RT-PCR) test between 15 May 2021 and 17 September 2021, at least three weeks after their second vaccine injection, had not received a third vaccine injection, and had no history of covid-19 infection. MAIN OUTCOME MEASURES: Positive result for the RT-PCR test. Individuals who tested positive for SARS-CoV-2 and controls were matched for week of testing, age category, and demographic group (ultra-orthodox Jews, individuals of Arab ancestry, and the general population). Conditional logistic regression was adjusted for age, sex, socioeconomic status, and comorbid conditions. RESULTS: 83 057 adults received an RT-PCR test for SARS-CoV-2 during the study period and 9.6% had a positive result. Time elapsed since the vaccine injection was significantly longer in individuals who tested positive (P<0.001). Adjusted odds ratio for infection at time intervals >90 days since vaccination were significantly increased compared with the reference of <90 days: 2.37 (95% confidence interval 1.67 to 3.36) for 90-119 days, 2.66 (1.94 to 3.66) for 120-149 days, 2.82 (2.07 to 3.84) for 150-179 days, and 2.82 (2.07 to 3.85) for ≥180 days (P<0.001 for each 30 day interval). CONCLUSIONS: In this large population of adults tested for SARS-CoV-2 by RT-PCR after two doses of mRNA BNT162b2 vaccine, a gradual increase in the risk of infection was seen for individuals who received their second vaccine dose after at least 90 days.

Large-Scale Study of Antibody Titer Decay following BNT162b2 mRNA Vaccine or SARS-CoV-2 Infection.

Immune protection following either vaccination or infection with SARS-CoV-2 is thought to decrease over time. We designed a retrospective study, conducted at Leumit Health Services in Israel, to determine the kinetics of SARS-CoV-2 IgG antibodies following administration of two doses of BNT162b2 vaccine, or SARS-CoV-2 infection in unvaccinated individuals. Antibody titers were measured between 31 January 2021, and 31 July 2021 in two mutually exclusive groups: (i) vaccinated individuals who received two doses of BNT162b2 vaccine and had no history of previous infection with COVID-19 and (ii) SARS-CoV-2 convalescents who had not received the vaccine. A total of 2653 individuals fully vaccinated by two doses of vaccine during the study period and 4361 convalescent patients were included. Higher SARS-CoV-2 IgG antibody titers were observed in vaccinated individuals (median 1581 AU/mL IQR [533.8-5644.6]) after the second vaccination than in convalescent individuals (median 355.3 AU/mL IQR [141.2-998.7]; p < 0.001). In vaccinated subjects, antibody titers decreased by up to 38% each subsequent month while in convalescents they decreased by less than 5% per month. Six months after BNT162b2 vaccination 16.1% subjects had antibody levels below the seropositivity threshold of <50 AU/mL, while only 10.8% of convalescent patients were below <50 AU/mL threshold after 9 months from SARS-CoV-2 infection. This study demonstrates individuals who received the Pfizer-BioNTech mRNA vaccine have different kinetics of antibody levels compared to patients who had been infected with the SARS-CoV-2 virus, with higher initial levels but a much faster exponential decrease in the first group.

Elapsed time since BNT162b2 vaccine and risk of SARS-CoV-2 infection in a large cohort.

IMPORTANCE: Israel was among the first countries to launch a large-scale COVID-19 vaccination campaign, and quickly vaccinated its population, achieving early control over the spread of the virus. However, the number of COVID-19 cases is now rapidly increasing, which may indicate that vaccine protection decreases over time. OBJECTIVE: To determine whether time elapsed since the second BNT162b2 messenger RNA (mRNA) vaccine (Pfizer-BioNTech) injection is significantly associated with the risk of post-vaccination COVID-19 infection. DESIGN: This is a retrospective cohort study performed in a large state-mandated health care organization in Israel. PARTICIPANTS: All fully vaccinated adults who have received a RT-PCR test between May 15, 2021 and July 26, 2021, at least two weeks after their second vaccine injection were included. Patients with a history of past COVID-19 infection were excluded. MAIN OUTCOME AND MEASURE: Positive result for the RT-PCR test. RESULTS: The cohort included 33,993 fully vaccinated adults, 49% women, with a mean age of 47 years (SD, 17 years), who received an RT-PCR test for SARS-CoV-2 during the study period. The median time between the second dose of the vaccine and the RT-PCR test was 146 days, interquartile range [121-167] days. 608 (1.8%) patients had positive test results. There was a significantly higher rate of positive results among patients who received their second vaccine dose at least 146 days before the RT-PCR test compared to patients who have received their vaccine less than 146 days before: odds ratio for infection was 3.00 for patients aged over 60 (95% CI 1.86-5.11); 2.29 for patients aged between 40 and 59 (95% CI 1.67-3.17); and 1.74 for patients aged between 18 and 39 (95% CI 1.27-2.37); P<0.001 in each age group. CONCLUSIONS AND RELEVANCE: In this large population study of patients tested for SARS-CoV-2 by RT-PCR following two doses of mRNA BNT162b2 vaccine, we observe a significant increase of the risk of infection in individuals who received their last vaccine dose since at least 146 days ago, particularly among patients older than 60.

Multi-center nationwide comparison of seven serology assays reveals a SARS-CoV-2 non-responding seronegative subpopulation.

BACKGROUND: An Israeli national taskforce performed a multi-center clinical and analytical validation of seven serology assays to determine their utility and limitations for SARS-CoV-2 diagnosis. METHODS: Serology assays from Roche, Abbott, Diasorin, BioMerieux, Beckman-Coulter, Siemens, and an in-house RBD ELISA were included. Negative samples from 2391 individuals representative of the Israeli population, and 698 SARS-CoV-2 PCR positive patients, collected between March and May 2020, were analyzed. FINDINGS: Immunoassays sensitivities between 81.5%-89.4% and specificities between 97.7%-100% resulted in a profound impact on the expected Positive Predictive Value (PPV) in low (<15%) prevalence scenarios. No meaningful increase was detected in the false positive rate in children compared to adults. A positive correlation between disease severity and antibody titers, and no decrease in antibody titers in the first 8 weeks after PCR positivity was observed. We identified a subgroup of symptomatic SARS-CoV-2 positive patients (~5% of patients), who remained seronegative across a wide range of antigens, isotypes, and technologies. INTERPRETATION: The commercially available automated immunoassays exhibit significant differences in performance and expected PPV in low prevalence scenarios. The low false-positivity rate in under 20's suggests that cross-reactive immunity from previous CoV strains is unlikely to explain the milder disease course in children. Finding no decrease in antibody titers in the first 8 weeks is in contrast to some reports of short half-life for SARS-CoV-2 antibodies. The ~5% who were seronegative non-responders, using multiple assays in a population-wide manner, represents the proportion of patients that may be at risk for re-infection. FUNDING: Israel Ministry of Health.

YbeY, a heat shock protein involved in translation in Escherichia coli.

Here we provide evidence that YbeY, a conserved heat shock protein with unknown function, is involved in the translation process. ybeY deletion mutants are temperature sensitive and have a significantly reduced thermotolerance. Nonetheless, there appears to be no damage of the protein quality control of mature polypeptides, as the levels of chaperones and proteases are normal and there is no accumulation of aggregates. Rather, the mutation results in a significant reduction in the level of polysomes, and upon a shift to a restrictive temperature (42 degrees C), there is an immediate and severe slowdown of translation. Taken together, the data indicate that YbeY is an important factor for bacterial translation even at 37 degrees C but becomes essential at high temperatures.

Adaptation of Escherichi coli to elevated temperatures involves a change in stability of heat shock gene transcripts.

Bacteria respond to shift-up in temperature by activating the heat shock response - induction of a large number of heat shock genes. This response is essential for adaptation to the higher temperature and for acquiring thermotolerance. One unique feature of the heat shock response is its transient nature - shortly after the induction, the rate of synthesis of heat shock proteins decreases, even if the temperature remains high. Here we show that this shutoff is due to a decrease in the transcript stability of heat shock genes. We further show that the modulation of stability of mRNAs of heat shock genes is maintained by the cold shock protein C - CspC - previously shown to affect transcript stability of specific genes. Upon shifts to higher temperatures the level of this protein decreases due to proteolysis and aggregation, leading to a reduced stability of mRNAs of heat shock genes. The temperature-dependent modulation of transcript stability of heat shock genes constitutes a novel control of the bacterial response to temperature changes.

Resistance to environmental stress requires the RNA chaperones CspC and CspE.

Stress response is essential for adaptation and for survival during environmental changes. A major factor in these responses is RpoS (σS), the master regulator of stationary phase and of the general stress response in Escherichia coli. RpoS is regulated by a complex network at several levels - transcription, translation and proteolysis. Previous studies indicated that rpoS transcripts are stabilized by overexpression of the cold shock proteins CspC and CspE. Here we demonstrate the importance of this transcript stabilization in the regulatory networks governing σS activity. We show that upon entry into stationary-phase rpoS transcripts are stabilized and this stabilization is necessary for the increased activity of σS. The increase in rpoS transcript stability requires at least one of the cold shock proteins CspC and CspE. We also show that the cellular concentration of CspC - but not CspE - increases concurrently with the increase in rpoS transcript stability, probably accounting for this stabilization. These data expand previous data showing that upon heat shock there is a reduction in CspC levels, coupled to a reduced half-life of heat shock gene transcripts. Taken together, it appears that CspC levels modulate transcript stability upon exposure to environmental stress while CspE acts as a 'housekeeping RNA chaperone' under general stress conditions.

CspC regulates rpoS transcript levels and complements hfq deletions.

The general stress response in Escherichia coli is activated by several stress agents, including entering the stationary growth phase. This response constitutes a complex regulatory network in which a large number of genes are induced and others are repressed. The stress response is regulated by the alternative sigma factor σ(S) encoded by the rpoS gene. The rpoS transcripts are substrates of the RNA binding protein, Hfq, which is essential for its translation. The rpoS mRNA is also a substrate of the cold shock protein C (CspC) which stabilizes the transcripts. Here we demonstrate, using pull-down assays, that CspC interacts with Hfq via mRNA molecules. We also show that CspC acts on the 5' UTR of the rpoS transcript, but its activity on rpoS is independent of Hfq. Moreover, we show that CspC suppresses the phenotypes of an hfq deletion. These results elucidate a new aspect in the post-transcriptional regulation of the stress response and will further our understanding of this complex network.

Temperature-dependent proteolysis as a control element in Escherichia coli metabolism.

Escherichia coli can grow at a broad temperature range, from less than 20 degrees C up to 45 degrees C. An increase in temperature results in a major physiological change, as enzymes work faster but, on the other hand, proteins tend to unfold. Therefore, a shift-up in temperature results in the induction of several regulatory response mechanisms aimed at restoring balanced growth at the new temperature. One important mechanism involves temperature-dependent proteolysis, which constitutes a fast response to temperature shift-ups. Here we discuss the effect of proteolysis on protein synthesis, and the heat shock response.

Thermoregulation of Escherichia coli hchA transcript stability.

The conserved chaperone Hsp31 of Escherichia coli is transcribed at low temperatures by sigma(S) and repressed by H-NS, whereas at high temperature, transcription is by sigma70 independently of both sigma(S) and H-NS. Here we present evidence for an additional, novel, temperature-dependent control of Hsp31 expression by increased transcript stability.