Vaccination with BNT162b2 reduces transmission of SARS-CoV-2 to household contacts in Israel

The effectiveness of vaccines against COVID-19 on the individual level is well established. However, few studies have examined vaccine effectiveness against transmission. We used a chain binomial model to estimate the effectiveness of vaccination with BNT162b2 [Pfizer-BioNTech messenger RNA (mRNA)-based vaccine] against household transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Israel before and after emergence of the B.1.617.2 (Delta) variant. Vaccination reduced susceptibility to infection by 89.4% [95% confidence interval (CI): 88.7 to 90.0%], whereas vaccine effectiveness against infectiousness given infection was 23.0% (95% CI: -11.3 to 46.7%) during days 10 to 90 after the second dose, before 1 June 2021. Total vaccine effectiveness was 91.8% (95% CI: 88.1 to 94.3%). However, vaccine effectiveness is reduced over time as a result of the combined effect of waning of immunity and emergence of the Delta variant.

SARS-CoV-2 RT-qPCR Test Detection Rates Are Associated with Patient Age, Sex, and Time since Diagnosis

Quantifying the detection rate of the widely used quantitative RT-PCR (RT-qPCR) test for severe acute respiratory syndrome coronavirus 2 and its dependence on patient demographic characteristics and disease progression is key in designing epidemiologic strategies. Analyzing 843,917 test results of 521,696 patients, a "positive period" was defined for each patient between diagnosis of coronavirus disease 2019 and the last positive test result. The fraction of positive test results within this period was then used to estimate detection rate. Regression analyses were used to determine associations of detection with time of sampling after diagnosis, patient demographic characteristics, and viral RNA copy number based on RT-qPCR cycle threshold values of the next positive test result. The overall detection rate in tests performed within 14 days after diagnosis was 83.1%. This rate was higher at days 0 to 5 after diagnosis (89.3%). Furthermore, detection rate was strongly associated with age and sex. Finally, the detection rate with the Allplex 2019-nCoV RT-qPCR kit was associated, at the single-patient level, with viral RNA copy number (P < 10^-9). These results show that the reliability of the test result is reduced in later days as well as for women and younger patients, in whom the viral loads are typically lower.

Odds of Testing Positive for SARS-CoV-2 Following Receipt of 3 vs 2 Doses of the BNT162b2 mRNA Vaccine

IMPORTANCE

With the evidence of waning immunity of the mRNA vaccine BNT162b2 (Pfizer-BioNTech), a nationwide third-dose (booster) vaccination campaign was initiated in Israel during August 2021; other countries have begun to administer a booster shot as well.

OBJECTIVE

To evaluate the initial short-term additional benefit of a 3-dose vs a 2-dose regimen against infection of SARS-CoV-2.

DESIGN, SETTING, AND PARTICIPANTS

This preliminary retrospective case-control study used 2 complementary approaches: a test-negative design and a matched case-control design. Participants were included from the national centralized database of Maccabi Healthcare Services, an Israeli healthcare maintenance organization covering 2.5 million members. Data were collected between March 1, 2020, and October 4, 2021, and analyses focused on the period from August 1, 2021, to October 4, 2021, because the booster dose was widely administered from August 1 onward.

EXPOSURES

Either 2 doses or 3 doses of the BNT162b2 vaccine.

MAIN OUTCOMES AND MEASURES

The reduction in the odds of a positive SARS-CoV-2 polymerase chain reaction (PCR) test at different time intervals following receipt of the booster dose (0-6, 7-13, 14-20, 21-27, and 28-65 days) compared with receiving only 2 doses.

RESULTS

The study population included 306 710 members of Maccabi Healthcare Services who were 40 years and older (55% female) and received either 2 or 3 doses of the BNT162b2 vaccine and did not have a positive PCR test result for SARS-CoV-2 prior to the start of the follow-up period. During this period, there were 500 232 PCR tests performed, 227 380 among those who received 2 doses and 272 852 among those who received 3 doses, with 14 989 (6.6%) and 4941 (1.8%) positive test results in each group, respectively. Comparing those who received a booster and those who received 2 doses, there was an estimated odds ratio of 0.14 (95% CI, 0.13-0.15) 28 to 65 days following receipt of the booster (86% reduction in the odds of testing positive for SARS-CoV-2).

CONCLUSION AND RELEVANCE

Previous studies have demonstrated that vaccine-derived protection against SARS-CoV-2 wanes over time. In this case-control analysis, we showed an association between receipt of the booster dose and a reduction in the odds of testing positive for SARS-CoV-2, potentially counteracting waning immunity in the short term. Further monitoring of data from this population is needed to determine the duration of immunity following the booster.

Waning Effectiveness of the BNT162b2 Vaccine Against Infection in Adolescents

BACKGROUND

The short-term effectiveness of a two-dose regimen of the BioNTech/Pfizer mRNA BNT162b2 vaccine for adolescents has been demonstrated. However, little is known about the long-term effectiveness in this age group. It is known, though, that waning of vaccine-induced immunity against infection in adult populations is evident within a few months.

METHODS

Leveraging the centralized computerized database of Maccabi Healthcare Services (MHS), we conducted a matched case-control design for evaluating the association between time since vaccination and the incidence of infections, where two outcomes were evaluated separately: a documented SARS-CoV-2 infection (regardless of symptoms) and a symptomatic infection (COVID-19). Cases were defined as individuals aged 12 to 16 with a positive PCR test occurring between June 15 and December 8, 2021, when the Delta variant was dominant in Israel. Controls were adolescents who had not tested positive previously.

RESULTS

We estimated a peak vaccine effectiveness between 2 weeks and 3 months following receipt of the second dose, with 85% and 90% effectiveness against SARS-CoV-2 infection and COVID-19, respectively. However, in line with previous findings for adults, waning of vaccine effectiveness was evident in adolescents as well. Long-term protection conferred by the vaccine was reduced to 75-78% against infection and symptomatic infection, respectively, 3 to 5 months after the second dose, and waned to 58% against infection and 65% against COVID-19 after 5 months.

CONCLUSIONS

Like adults, vaccine-induced protection against both SARS-CoV-2 infection and COVID-19 wanes with time, starting three months after inoculation and continuing for more than five months.

Dynamics in COVID-19 symptoms during different waves of the pandemic among children infected with SARS-CoV-2 in the ambulatory setting

The aim of this real-life, big data population-based study was to evaluate differences in symptomatic presentation of children infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) between the third and fourth waves of the pandemic in Israel, dominated by the Alpha and Delta variants, respectively. Our cohort included all children and adolescents, members of the second-largest Health Maintenance Organization in Israel that had positive real-time polymerase chain reaction (RT-PCR) test during the third and fourth waves of the pandemic (December 1, 2020, to April 30, 2021, and June 1, 2021, to October 10, 2021, respectively). A total of 32,485 and 44,130 children and adolescents in the third and fourth waves were included in the final analysis. The rate of children with symptomatic disease among patients with documented SARS-CoV-2 infection was higher in the fourth wave compared to the third wave (49.9% vs. 37.5%). The most commonly reported symptom and the only symptom that substantially differed between waves was fever, with 33% of SARS-CoV-2 infected children in the fourth wave vs. 13.6% in the third wave. Preschool children had the lowest prevalence of febrile illness compared to other age groups.

CONCLUSION

Children and adolescents infected during the fourth wave of the pandemic in Israel, a Delta-dominant period, had a significantly higher rate of symptomatic febrile illness than the Alpha-dominant period. This phenomenon occurred across all age groups.

WHAT IS KNOWN

• There are differences in COVID-19 severity among adults and children during different waves of the pandemic. • There is a paucity of data regarding symptomatic characteristics in children in large-scale cohorts aside from hospital settings.

WHAT IS NEW

• In a time period dominated by the Delta variant, there were substantially more children with symptomatic disease and febrile illness compared to a period dominated by the alpha variant. • Preschool children had the lowest rate of febrile illness among all age groups.

Vaccination with BNT162b2 reduces transmission of SARS-CoV-2 to household contacts in Israel

The individual-level effectiveness of vaccines against clinical disease caused by SARS-CoV-2 is well-established. However, few studies have directly examined the effect of COVID-19 vaccines on transmission. We quantified the effectiveness of vaccination with BNT162b2 (Pfizer-BioNTech mRNA-based vaccine) against household transmission of SARS-CoV-2 in Israel. We fit two time-to-event models - a mechanistic transmission model and a regression model - to estimate vaccine effectiveness against susceptibility to infection and infectiousness given infection in household settings. Vaccine effectiveness against susceptibility to infection was 80-88%. For breakthrough infections among vaccinated individuals, the vaccine effectiveness against infectiousness was 41-79%. The overall vaccine effectiveness against transmission was 88.5%. Vaccination provides substantial protection against susceptibility to infection and slightly lower protection against infectiousness given infection, thereby reducing transmission of SARS-CoV-2 to household contacts.

ONE-SENTENCE SUMMARY

Vaccination reduced both the rate of infection with SARS-CoV-2 and transmission to household contacts in Israel.

Evaluating red blood cell distribution width from community blood tests as a predictor of hospitalization and mortality in adults with SARS-CoV-2: a cohort study

BACKGROUND

Red blood cell distribution width (RDW) has been assessed during COVID-19 patient hospitalization, however, further research should be done to evaluate RDW from routine community blood tests, before infection, as a risk factor for COVID-19 related hospitalization and mortality.

PATIENTS AND METHODS

RDW was measured as a predictor along with age, sex, chronic illnesses, and BMI in logistic regressions to predict hospitalization and mortality. Hospitalization and mortality odds ratios (ORs) were estimated with 95% confidence intervals (CI). RDW was evaluated separately as continuous and discrete (High RDW ≥ 14.5) variables.

RESULTS

Four thousand one hundred and sixty-eight patients were included in this study, where 824 patients (19.8%) had a high RDW value ≥14.5% (High RDW: 64.7% were female, mean age 58 years [±22] vs. Normal RDW: 60.2% female, mean age 46 years [±19]). Eight hundred and twenty-nine patients had a hospitalization, where the median time between positive PCR and hospital entry was 5 [IQR 1-18] days. Models were analyzed with RDW (continuous) and adjusted for age, sex, comorbidities, and BMI suggested an OR of 1.242 [95% CI = 1.187-2.688] for hospitalization and an OR of 2.911 [95% CI = 1.928-4.395] for mortality (p < .001). RDW (discrete) with the same adjustments presented an OR of 2.232 [95% CI = 1.853-1.300] for hospitalization and an OR of 1.263 [95% CI = 1.166-1.368] for mortality (p < .001).

CONCLUSIONS

High RDW values obtained from community blood tests are associated with greater odds of hospitalization and mortality for patients with COVID-19.KEY MESSAGESRDW measures before SARS-CoV-2 infection is a predictive factor for hospitalization and mortality.RDW threshold of 14.5% provides high sensitivity and specificity for COVID-19 related mortality, comparatively to other blood tests.Patient records should be accessed by clinicians for prior RDW results, if available, followed by further monitoring.

Correlation of SARS-CoV-2-breakthrough infections to time-from-vaccine

The short-term effectiveness of a two-dose regimen of the BioNTech/Pfizer mRNA BNT162b2 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine was widely demonstrated. However, long term effectiveness is still unknown. Leveraging the centralized computerized database of Maccabi Healthcare Services (MHS), we assessed the correlation between time-from-vaccine and incidence of breakthrough infection between June 1 and July 27, the date of analysis. After controlling for potential confounders as age and comorbidities, we found a significant 1.51 fold (95% CI, 1.38-1.66) increased risk for infection for early vaccinees compared to those vaccinated later that was similar across all ages groups. The increased risk reached 2.26- fold (95% CI, 1.80-3.01) when comparing those who were vaccinated in January to those vaccinated in April. This preliminary finding of vaccine waning as a factor of time from vaccince should prompt further investigations into long-term protection against different strains.

Kinetics of SARS-CoV-2 anti-S IgG after BNT162b2 vaccination

Deployment of the BNT162b2 mRNA Covid-19 Vaccine in Israel began in December 2020.

This is a retrospective analysis of serological data, showing SARS-CoV-2 anti-S IgG kinetics in 116 Israeli health care workers receiving BNT162b2.

Sero-conversion occurred in 14 days in all study participants, with IgG levels peaking approximately 30 days after initiation of the vaccination series.

A statistically significant difference was observed in IgG levels between subjects younger than 50 years and older participants, although in all cases, IgG levels were well above the level considered reactive by the test's manufacturer.

The importance of this difference needs to be studied further, but a potential difference in vaccine efficacy and vaccine effect length could possibly be present between these two groups.

A multi-layer model for the early detection of COVID-19

Current COVID-19 screening efforts mainly rely on reported symptoms and the potential exposure to infected individuals. Here, we developed a machine-learning model for COVID-19 detection that uses four layers of information: (i) sociodemographic characteristics of the individual, (ii) spatio-temporal patterns of the disease, (iii) medical condition and general health consumption of the individual and (iv) information reported by the individual during the testing episode. We evaluated our model on 140 682 members of Maccabi Health Services who were tested for COVID-19 at least once between February and October 2020. These individuals underwent, in total, 264 516 COVID-19 PCR tests, out of which 16 512 were positive. Our multi-layer model obtained an area under the curve (AUC) of 81.6% when evaluated over all the individuals in the dataset, and an AUC of 72.8% when only individuals who did not report any symptom were included. Furthermore, considering only information collected before the testing episode-i.e. before the individual had the chance to report on any symptom-our model could reach a considerably high AUC of 79.5%. Our ability to predict early on the outcomes of COVID-19 tests is pivotal for breaking transmission chains, and can be used for a more efficient testing policy.

Assessment of Effectiveness of 1 Dose of BNT162b2 Vaccine for SARS-CoV-2 Infection 13 to 24 Days After Immunization

IMPORTANCE

The BNT162b2 vaccine showed high efficacy against COVID-19 in a phase III randomized clinical trial. A vaccine effectiveness evaluation in a real-world setting is needed.

OBJECTIVE

To assess the short-term effectiveness of the first dose of the BNT162b2-vaccine against SARS-CoV-2 infection 13 to 24 days after immunization in a real-world setting.

DESIGN, SETTING, AND PARTICIPANTS

This comparative effectiveness study used data from a 2.6 million-member state-mandated health care system in Israel. Participants included all individuals aged 16 years and older who received 1 dose of the BNT162b2 vaccine between December 19, 2020, and January 15, 2021. Data were analyzed in March 2021.

EXPOSURE

Receipt of 1 dose of the BNT162b2 vaccine.

MAIN OUTCOMES AND MEASURES

Information was collected regarding medical history and positive SARS-CoV-2 polymerase chain reaction test and COVID-19 symptoms from 1 day after first vaccine to January 17, 2021. Daily and cumulative infection rates in days 13 to 24 were compared with days 1 to 12 after the first dose using Kaplan-Meier survival analysis and generalized linear models.

RESULTS

Data for 503 875 individuals (mean [SD] age, 59.7 [14.7] years; 263 228 [52.4%] women) were analyzed, of whom 351 897 had follow-up data for days 13 to 24. The cumulative incidence of SARS-CoV-2 infection was 2484 individuals (0.57%) during days 1 through 12 and 614 individuals (0.27%) in days 13 through 24. The weighted mean (SE) daily incidence of SARS-CoV-2 infection in days 1 through 12 was 43.41 (12.07) infections per 100 000 population and 21.08 (6.16) infections per 100 000 population in days 13 through 24, a relative risk reduction (RRR) of 51.4% (95% CI, 16.3%-71.8%). The decrease in incidence was evident from day 18 after the first dose. Similar RRRs were calculated in individuals aged 60 years or older (44.5%; 95% CI, 4.1%-67.9%), those younger than 60 years (50.2%; 95% CI, 14.1%-71.2%), women (50.0%; 95% CI, 13.5%-71.0%), and men (52.1%; 95% CI, 17.3%-72.2%). Findings were similar in subpopulations (eg, ultraorthodox Jewish: RRR, 53.5% [95% CI, 19.2%-73.2%]) and patients with various comorbidities (eg, cardiovascular diseases: RRR, 47.2% [95% CI, 7.8%-69.8%]). Vaccine effectiveness against symptomatic COVID-19 was 54.4% (95% CI, 21.4%-73.6%).

CONCLUSIONS AND RELEVANCE

In this comparative effectiveness study of a single dose of the BNT162b2 vaccine, results were comparable to that of the phase III randomized clinical trial.

The effectiveness of the TWO-DOSE BNT162b2 vaccine: analysis of real-world data

Background

COVID-19 mRNA vaccines were shown to be highly efficacious in preventing the disease in randomized controlled trials; nonetheless, evidence on the real-world effectiveness of this vaccine is limited. Study objective was to evaluate the effectiveness of BNT162b2 vaccine in preventing SARS-CoV-2 infection and COVID-19-related hospitalization and mortality.

Methods

This historical cohort study included members of a large health provider in Israel that were vaccinated with at least one dose of BNT162b2. The primary outcome was incidence rate of a SARS-CoV-2 infection confirmed with rt-PCR, between 7 to 27 days after second dose (protection-period), as compared to days 1 to 7 after the first dose, where no protection by the vaccine is assumed (reference-period).

Results

Data of 1,178,597 individuals vaccinated with BNT162b2 were analyzed (mean age 47.7 years [SD=18.1], 48.4% males) of whom 872,454 (74.0%) reached the protection period. Overall, 4514 infections occurred during the reference period compared to 728 during the protection period, yielding a weighted mean daily incidence of 54.8 per 100,000 (95%CI: 26.1-115.0 per 100,000) and 5.4 per 100,000 (95%CI: 3.5-8.4 per 100,000), respectively. The vaccine effectiveness in preventing infection was 90% (95%CI:79%- 95%) and 94% (95%CI:88%-97%) against COVID-19. Among immunosuppressed patients, vaccine effectiveness against infection was 71% (95%CI:37%-87%). The adjusted hazard ratios for hospitalization in those infected were 0.82 (95%CI:0.36-1.88), 0.45 (95%CI:0.23-0.90), and 0.56 (95%CI:0.36-0.89) in the age groups 16-44, 45-64 and 75 and above, respectively.

Conclusions

The effectiveness of the BNT162b2 vaccine is comparable to the one reported in the phase III clinical trial.

Initial report of decreased SARS-CoV-2 viral load after inoculation with the BNT162b2 vaccine

Beyond their substantial protection of individual vaccinees, coronavirus disease 2019 (COVID-19) vaccines might reduce viral load in breakthrough infection and thereby further suppress onward transmission. In this analysis of a real-world dataset of positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test results after inoculation with the BNT162b2 messenger RNA vaccine, we found that the viral load was substantially reduced for infections occurring 12-37 d after the first dose of vaccine. These reduced viral loads hint at a potentially lower infectiousness, further contributing to vaccine effect on virus spread.

Improving techniques for diagnostics of laser pulses by compact representations

We propose and demonstrate, numerically and experimentally, use of sparsity as prior information for extending the capabilities and performance of techniques and devices for laser pulse diagnostics. We apply the concept of sparsity in three different applications. First, we improve a photodiode-oscilloscope system's resolution for measuring the intensity structure of laser pulses. Second, we demonstrate the intensity profile reconstruction of ultrashort laser pulses from intensity autocorrelation measurements. Finally, we use a sparse representation of pulses (amplitudes and phases) to retrieve measured pulses from incomplete spectrograms of cross-correlation frequency-resolved optical gating traces.

Downwards Vertical Attention Bias in Conversion Disorder vs Controls: A Pilot Study

BACKGROUND

Conversion disorder (CD) is a largely enigmatic disorder, one that requires a thorough ruling-out process. Prior research suggests that metaphors and conceptualization are rooted in physical experience, and that we interpret our affective world through metaphors. Spatial metaphors (interaction of affect and vertical space) are a prominent example of the grounding of metaphors. This is a relatively unpaved direction of research of CD.

OBJECTIVES

The present pilot study sought to explore this view by investigating the "healthy is up, sick is down" spatial metaphors (e.g., "fell ill" and "top shape") in patients with CD, examining the correlation between the processing of bodily-related words, CD, and vertical space. We hypothesized that patients with CD, who experience their bodies as ill, will demonstrate a downwards bias when processing bodily-related words; corresponding to the "healthy is up, sick is down" spatial metaphor.

METHODS

A total of 8 female patients (ages M-38.13 SD-10.44) and 42 female controls (ages M-36.4 SD-14.57) performed a visual attention task. Participants were asked to identify a spatial probe at the top or the bottom of a screen, following either a bodily related (e.g., arm) or non-bodily related (e.g., clock) prime word.

RESULTS

As predicted, when processing bodily-related words, patients with CD demonstrated a downwards attention bias. Moreover, the higher the patient's level of somatization, the faster the patient detected lower (vs upper) spatial targets.

CONCLUSIONS

This study suggests that the changed health paradigm of patients with CD is grounded in sensorimotor perception. Further research could propose new diagnostic and treatment options for CD.

Sparsity-based single-shot subwavelength coherent diffractive imaging

Coherent Diffractive Imaging (CDI) is an algorithmic imaging technique where intricate features are reconstructed from measurements of the freely diffracting intensity pattern. An important goal of such lensless imaging methods is to study the structure of molecules that cannot be crystallized. Ideally, one would want to perform CDI at the highest achievable spatial resolution and in a single-shot measurement such that it could be applied to imaging of ultrafast events. However, the resolution of current CDI techniques is limited by the diffraction limit, hence they cannot resolve features smaller than one half the wavelength of the illuminating light. Here, we present sparsity-based single-shot subwavelength resolution CDI: algorithmic reconstruction of subwavelength features from far-field intensity patterns, at a resolution several times better than the diffraction limit. This work paves the way for subwavelength CDI at ultrafast rates, and it can considerably improve the CDI resolution with X-ray free-electron lasers and high harmonics.

Somatic embryos from culture ovules of polyembryonic Mangifera indica L

Ovules were aseptically removed from 2 month old fruits of 9 naturally polyembryonic cultivars and 1 monoembryonic cultivar of mango (Mangifera indica L.). Ovules were placed into culture on solid Murashige and Skoog medium that had been modified by the addition of half strength major salts and chelated iron, 6% sucrose, 400 mg/l glutamine, 100 mg/l ascorbic acid with or without the following growth regulators: 20% (v/v) CW, 1 or 2 mg/1 BA. Somatic embryogenesis occurred from the nucellus excised from the ovules of 5 of the naturally polyembryonic cultivars after 1-2 months in culture. Somatic embryogenesis was not apparently affected by the growth regulator composition of the media; however, efficient somatic embryogenesis only occurred in liquid containing 20% CW.