Effectiveness of the ChAdOx1 vaccine in the elderly during SARS-CoV-2 Gamma variant transmission in Brazil

Background A two-dose regimen of ChAdOx1 coronavirus disease 19 (Covid-19) vaccine with an inter-dose interval of three months has been implemented in many countries with restricted vaccine supply. However, there is limited evidence for the effectiveness of ChAdOx1 by dose in elderly populations in countries with high prevalence of the Gamma variant of severe acute respiratory syndrome 2 (SARS-CoV-2). Methods We conducted a test-negative case-control study to estimate the effectiveness of ChAdOx1 vaccine in adults aged 60 years or older during a Gamma-variant-associated epidemic in São Paulo state, Brazil, between 17 January and 2 July 2021. Cases and matched test-negative controls were individuals, identified from surveillance databases, who experienced an acute respiratory illness and underwent SARS-CoV-2 RT-PCR testing. We used conditional logistic regression to estimate the effectiveness by dose against RT-PCR-confirmed Covid-19, Covid-19 hospitalization, and Covid-19-related death. Results 61,164 individuals were selected into matched case-control pairs. Starting ≥28 days after the first dose, adjusted effectiveness of a single dose of ChAdOx1 was 33.4% (95% CI, 26.4 to 39.7) against Covid-19, 55.1% (95% CI, 46.6 to 62.2) against hospitalization, and 61.8% (95% CI, 48.9 to 71.4) against death. Starting ≥14 days after the second dose, the adjusted effectiveness of the two-dose schedule was 77.9% (95% CI, 69.2 to 84.2) against Covid-19, 87.6% (95% CI, 78.2 to 92.9) against hospitalization, and 93.6% (95% CI, 81.9 to 97.7) against death. Conclusions Completion of the ChAdOx1 vaccine schedule afforded significantly increased protection over a single dose against mild and severe Covid-19 outcomes in elderly individuals during widespread Gamma variant transmission.

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Effectiveness of ChAdOx1 vaccine in older adults during SARS-CoV-2 Gamma variant circulation in São Paulo

Nature Communications ◽

10.1038/s41467-021-26459-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Matt D. T. Hitchings ◽

Otavio T. Ranzani ◽

Murilo Dorion ◽

Tatiana Lang D’Agostini ◽

Regiane Cardoso de Paula ◽

...

Keyword(s):

Single Dose ◽

Dose Interval ◽

Dose Schedule ◽

Sao Paulo ◽

São Paulo ◽

Vaccine Schedule ◽

Negative Case ◽

High Prevalence ◽

High Gamma ◽

Secondary Endpoints

AbstractA two-dose regimen of the Oxford-AstraZeneca (ChAdOx1) Covid-19 vaccine with an inter-dose interval of three months has been implemented in many countries with restricted vaccine supply. However, there is limited evidence for the effectiveness of ChAdOx1 by dose in elderly populations in countries with high prevalence of the Gamma variant of SARS-CoV-2. Here, we estimate ChAdOx1 effectiveness by dose against the primary endpoint of RT-PCR-confirmed Covid-19, and secondary endpoints of Covid-19 hospitalization and Covid-19-related death, in adults aged ≥60 years during an epidemic with high Gamma variant prevalence in São Paulo state, Brazil using a matched, test-negative case-control study. Starting 28 days after the first dose, effectiveness of a single dose of ChAdOx1 is 33.4% (95% CI, 26.4–39.7) against Covid-19, 55.1% (95% CI, 46.6–62.2) against hospitalization, and 61.8% (95% CI, 48.9–71.4) against death. Starting 14 days after the second dose, effectiveness of the two-dose schedule is 77.9% (95% CI, 69.2–84.2) against Covid-19, 87.6% (95% CI, 78.2–92.9) against hospitalization, and 93.6% (95% CI, 81.9–97.7) against death. Completion of the ChAdOx1 vaccine schedule affords significantly increased protection over a single dose against mild and severe Covid-19 outcomes in elderly individuals during widespread Gamma variant circulation.

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Effectiveness of the CoronaVac vaccine in the elderly population during a P.1 variant-associated epidemic of COVID-19 in Brazil: A test-negative case-control study

10.1101/2021.05.19.21257472 ◽

2021 ◽

Author(s):

Otavio T. Ranzani ◽

Matt Hitchings ◽

Murilo Dorion Neto ◽

Tatiana Lang D'Agostini ◽

Regiane Cardoso de Paula ◽

...

Keyword(s):

Dose Regimen ◽

Elderly Population ◽

Case Control Study ◽

The Elderly ◽

Case Control ◽

Vaccine Effectiveness ◽

Rt Pcr ◽

Paulo State ◽

Negative Case ◽

Control Study

Background Mass vaccination is being used in response to coronavirus disease (COVID-19) epidemics, including those driven by emerging variants of concern. We evaluated the effectiveness of the inactivated whole-virus vaccine, CoronaVac, against symptomatic COVID-19 in the elderly population of Sao Paulo State, Brazil during widespread circulation of the P.1 variant. Methods We conducted a test-negative, case-control study of adults >=70 years of age from Sao Paulo State from January 17 to April 29, 2021, during which vaccination with a two-dose regimen of CoronaVac was implemented. We identified RT-PCR-confirmed COVID-19 cases and controls who had a symptomatic illness with a negative RT-PCR test from national surveillance and state vaccination databases. Controls were pair-matched to cases by age category, sex, race, municipality, prior COVID-19 status, and date of RT-PCR testing. We estimated vaccine effectiveness, adjusted for age and comorbidities, using conditional logistic regression. Findings We selected 7,950 matched pairs with a mean age of 76 years from 26,433 COVID-19 cases and 17,622 test-negative controls. Adjusted vaccine effectiveness was 18.2% (95% CI, 0.0 to 33.2) and 41.6% (95% CI, 26.9 to 53.3) in the period 0-13 and >=14 days, respectively, after the 2nd dose. Administration of a single vaccine dose was not associated with reduced odds of COVID-19. Vaccine effectiveness >=14 days after the 2nd dose declined with increasing age and was 61.8% (95% CI 34.8 to 77.7), 48.9% (95% CI 23.3 to 66.0) and 28.0% (95% CI 0.6 to 47.9) among individuals 70-74, 75-79 and >=80 years of age, respectively (p-interaction = 0.05). Interpretation CoronaVac was 42% effective in the real-world setting of extensive P.1 transmission, but significant protection was not observed until completion of the two-dose regimen. These findings underscore the need to maintain non-pharmaceutical interventions when mass vaccination with CoronaVac is used as part of an epidemic response. Funding Pan American Health Organization

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Effectiveness of CoronaVac in the setting of high SARS-CoV-2 P.1 variant transmission in Brazil: A test-negative case-control study

10.1101/2021.04.07.21255081 ◽

2021 ◽

Author(s):

Matt Hitchings ◽

Otavio T. Ranzani ◽

Mario S.S. Torres ◽

Silvano Barbosa de Oliveira ◽

Maria Almiron ◽

...

Keyword(s):

Case Control Study ◽

Conditional Logistic Regression ◽

Case Control ◽

Vaccine Effectiveness ◽

Rt Pcr ◽

Fold Reduction ◽

Negative Case ◽

Health Organization ◽

Negative Controls ◽

Control Study

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant P.1 emerged in the city of Manaus in late 2020 during a large resurgence of coronavirus disease (COVID-19), and has spread throughout Brazil. The effectiveness of vaccines in settings with widespread P.1 transmission has not been reported. Methods We performed a matched test-negative case-control study to estimate the effectiveness of an inactivated vaccine, CoronaVac, in healthcare workers (HCWs) in Manaus, where P.1 accounted for 75% of genotyped SARS-CoV-2 samples at the peak of its epidemic. Information from electronic surveillance databases was used to select cases of RT-PCR-confirmed SARS-CoV-2 infection and matched test-negative controls from 19 January, 2021 to 25 March, 2021. We used conditional logistic regression to estimate the effectiveness in reducing the odds of primary and secondary outcomes of, respectively, symptomatic and any SARS-CoV-2 infection. Findings Among 53,176 HCWs, 46,884 (88%) received at least one dose of CoronaVac and 2,656 (5%) underwent RT-PCR testing from 19 January, 2021 to 25 March, 2021. Of 2,797 RT-PCR tests, 776 (28%) were positive. 393 and 135 case-control pairs with and without, respectively, symptomatic illness were selected for the matched analyses. Vaccination with at least one dose was associated with a 0.50-fold reduction (adjusted vaccine effectiveness, 49.6%; 95% CI, 11.3 - 71.4) in the odds of symptomatic SARS-CoV-2 infection during the period 14 days or more after receiving the first dose. Estimated vaccine effectiveness of at least one dose against any SARS-CoV-2 infection was 35.1% (95% CI, -6.6 - 60.5) in the same time period. Interpretation Administration of at least one dose of CoronaVac showed effectiveness against symptomatic SARS-CoV-2 infection in the setting of epidemic P.1 transmission, underscoring the need to increase vaccination efforts in response to the spread of this variant in Brazil and globally. Funding Pan American Health Organization; Fundação Oswaldo Cruz (Fiocruz); Municipal Health Secretary of Manaus

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Effectiveness of CoronaVac, ChAdOx1, BNT162b2 and Ad26.COV2.S among individuals with prior SARS-CoV-2 infection in Brazil

10.1101/2021.12.21.21268058 ◽

2021 ◽

Author(s):

Thiago Cerqueira-Silva ◽

Jason R Andrews ◽

Viviane S Boaventura ◽

Otavio T Ranzani ◽

Vinicius de Araujo Oliveira ◽

...

Keyword(s):

Case Control Study ◽

Conditional Logistic Regression ◽

Case Control ◽

Rt Pcr ◽

Symptomatic Infection ◽

Series Completion ◽

Negative Controls ◽

Prior Infection ◽

Control Study ◽

Dose Vaccine

Background. COVID-19 vaccines have proven highly effective among SARS-CoV-2 naive individuals, but their effectiveness in preventing symptomatic infection and severe outcomes among individuals with prior infection is less clear. Methods. Utilizing national COVID-19 notification, hospitalization, and vaccination datasets from Brazil, we performed a case-control study using a test-negative design to assess the effectiveness of four vaccines (CoronaVac, ChAdOx1, Ad26.COV2.S and BNT162b2) among individuals with laboratory-confirmed prior SARS-CoV-2 infection. We matched RT-PCR positive, symptomatic COVID-19 cases with RT-PCR-negative controls presenting with symptomatic illnesses, restricting both groups to tests performed at least 90 days after an initial infection. We used multivariable conditional logistic regression to compare the odds of test positivity, and the odds of hospitalization or death due to COVID-19, according to vaccination status and time since first or second dose of vaccines. Findings. Among individuals with prior SARS-CoV-2 infection, vaccine effectiveness against symptomatic infection ≥ 14 days from vaccine series completion was 39.4% (95% CI 36.1-42.6) for CoronaVac, 56.0% (95% CI 51.4-60.2) for ChAdOx1, 44.0% (95% CI 31.5-54.2) for Ad26.COV2.S, and 64.8% (95% CI 54.9-72.4) for BNT162b2. For the two-dose vaccine series (CoronaVac, ChAdOx1, and BNT162b2), effectiveness against symptomatic infection was significantly greater after the second dose compared with the first dose. Effectiveness against hospitalization or death ≥ 14 days from vaccine series completion was 81.3% (95% CI 75.3-85.8) for CoronaVac, 89.9% (95% CI 83.5-93.8) for ChAdOx1, 57.7% (95% CI -2.6-82.5) for Ad26.COV2.S, and 89.7% (95% CI 54.3-97.7) for BNT162b2.

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COVID-19 symptoms: a case–control study, Portugal, March–April 2020

Epidemiology and Infection ◽

10.1017/s095026882100042x ◽

2021 ◽

Vol 149 ◽

Author(s):

M. Perez Duque ◽

H. Lucaccioni ◽

C. Costa ◽

R. Marques ◽

D. Antunes ◽

...

Keyword(s):

Case Control Study ◽

Gastrointestinal Symptoms ◽

Respiratory Illness ◽

Case Control ◽

Case Definition ◽

Clinical Criteria ◽

Negative Case ◽

Best Fit ◽

Symptoms And Signs ◽

Control Study

Abstract COVID-19, although a respiratory illness, has been clinically associated with non-respiratory symptoms. We conducted a negative case–control study to identify the symptoms associated with SARS-CoV-2-positive results in Portugal. Twelve symptoms and signs included in the clinical notification of COVID-19 were selected as predictors, and the dependent variable was the RT-PCR test result. The χ2 tests were used to compare notified cases on sex, age group, health region and presence of comorbidities. The best-fit prediction model was selected using a backward stepwise method with an unconditional logistic regression. General and gastrointestinal symptoms were strongly associated with a positive test (P < 0.001). In this sense, the inclusion of general symptoms such as myalgia, headache and fatigue, as well as diarrhoea, together with actual clinical criteria for suspected cases, already updated and included in COVID-19 case definition, can lead to increased identification of cases and represent an effective strength for transmission control.

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Association between coffee and green tea intake and pneumonia among the Japanese elderly: a case-control study

Scientific Reports ◽

10.1038/s41598-021-84348-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kyoko Kondo ◽

◽

Kanzo Suzuki ◽

Masakazu Washio ◽

Satoko Ohfuji ◽

...

Keyword(s):

Green Tea ◽

Case Control Study ◽

Conditional Logistic Regression ◽

The Elderly ◽

The United States ◽

Case Control ◽

Inverse Association ◽

Coffee Intake ◽

Conditional Logistic Regression Model ◽

Control Study

AbstractA large prospective cohort study in the United States examined the association between coffee intake and overall and cause-specific mortality and showed a inverse association between pneumonia and influenza deaths and coffee intake. In Japan, the mortality rate of pneumonia in elderly people is high, and its prevention is an important issue. The present study investigated the association between coffee and green tea intake and pneumonia among the elderly. The design was a hospital-based case control study. The cases were patients over 65 years old newly diagnosed as pneumonia. As a control, patients with the same sex and age (range of 5 years) who visited the same medical institution around the same time (within 2 months after examination of the case) for a disease other than pneumonia were selected. There were two controls per case. Odds ratio (OR) and 95% confidence interval (CI) for pneumonia of coffee and green tea intake during the past month were calculated using a conditional logistic regression model. A total of 199 cases and 374 controls were enrolled. When compared to those who do not drink coffee, the OR for pneumonia of those who drink less than one cup of coffee per day was 0.69 (95% CI 0.39–1.21), OR of those who drink one cup was 0.67 (0.38–1.18), and OR of those who drink two or more cups was 0.50 (0.28–0.88) (Trend p = 0.024). No association was found between pneumonia and green tea consumption. This study suggested a preventive association between coffee intake over 2 cups per day and pneumonia in the elderly.

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Effectiveness of mRNA-1273 against delta, mu, and other emerging variants of SARS-CoV-2: test negative case-control study

BMJ ◽

10.1136/bmj-2021-068848 ◽

2021 ◽

pp. e068848

Author(s):

Katia J Bruxvoort ◽

Lina S Sy ◽

Lei Qian ◽

Bradley K Ackerson ◽

Yi Luo ◽

...

Keyword(s):

Hospital Admission ◽

Case Control Study ◽

Conditional Logistic Regression ◽

Case Control ◽

Vaccine Effectiveness ◽

Specimen Collection ◽

Negative Case ◽

Delta Infection ◽

Control Study ◽

Dose Vaccine

Abstract Objectives To evaluate the effectiveness of the mRNA-1273 vaccine against SARS-CoV-2 variants and assess its effectiveness against the delta variant by time since vaccination. Design Test negative case-control study. Setting Kaiser Permanente Southern California (KPSC), an integrated healthcare system. Participants Adult KPSC members with a SARS-CoV-2 positive test sent for whole genome sequencing or a negative test from 1 March 2021 to 27 July 2021. Interventions Two dose or one dose vaccination with mRNA-1273 (Moderna covid-19 vaccine) ≥14 days before specimen collection versus no covid-19 vaccination. Main outcome measures Outcomes included infection with SARS-CoV-2 and hospital admission with covid-19. In pre-specified analyses for each variant type, test positive cases were matched 1:5 to test negative controls on age, sex, race/ethnicity, and specimen collection date. Conditional logistic regression was used to compare odds of vaccination among cases versus controls, with adjustment for confounders. Vaccine effectiveness was calculated as (1–odds ratio)×100%. Results The study included 8153 cases and their matched controls. Two dose vaccine effectiveness was 86.7% (95% confidence interval 84.3% to 88.7%) against infection with the delta variant, 98.4% (96.9% to 99.1%) against alpha, 90.4% (73.9% to 96.5%) against mu, 96-98% against other identified variants, and 79.9% (76.9% to 82.5%) against unidentified variants (that is, specimens that failed sequencing). Vaccine effectiveness against hospital admission with the delta variant was 97.5% (92.7% to 99.2%). Vaccine effectiveness against infection with the delta variant declined from 94.1% (90.5% to 96.3%) 14-60 days after vaccination to 80.0% (70.2% to 86.6%) 151-180 days after vaccination. Waning was less pronounced for non-delta variants. Vaccine effectiveness against delta infection was lower among people aged ≥65 years (75.2%, 59.6% to 84.8%) than those aged 18-64 years (87.9%, 85.5% to 89.9%). One dose vaccine effectiveness was 77.0% (60.7% to 86.5%) against infection with delta. Conclusions Two doses of mRNA-1273 were highly effective against all SARS-CoV-2 variants, especially against hospital admission with covid-19. However, vaccine effectiveness against infection with the delta variant moderately declined with increasing time since vaccination.

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Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against Pneumococcal Diseases Among the Elderly Aged 60 Years or Older: A Matched Test Negative Case-Control Study in Shanghai, China

Frontiers in Public Health ◽

10.3389/fpubh.2021.620531 ◽

2021 ◽

Vol 9 ◽

Author(s):

Xiaodong Sun ◽

Xiang Guo ◽

Jing Qiu ◽

Genming Zhao ◽

Xinxin Xu ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Pneumococcal Disease ◽

Case Control Study ◽

The Elderly ◽

Case Control ◽

Polysaccharide Vaccine ◽

Pneumococcal Polysaccharide Vaccine ◽

Negative Case ◽

Multiple Variables ◽

Control Study

Background:Streptococcus pneumoniae infection among adults, especially in adults over 60 years old in China results in a large number of hospitalizations and a substantial financial burden. This study assessed the vaccine effectiveness (VE) of 23-valent pneumococcal polysaccharide vaccine (PPV23) against pneumococcal diseases among the elderly aged 60 years or older in Shanghai, China.Methods: We conducted a test-negative case–control study among the elderly aged 60 years or older who sought care at hospitals in 13 districts of Shanghai from September 14, 2013 to August 31, 2019. A case was defined as pneumococcal disease and testing positive for Streptococcus pneumoniae. Controls had symptoms congruent with pneumococcal disease but were negative for Streptococcus pneumoniae. We conducted 1:2 matching by gender, age, hospital and admission date. Vaccination status was verified from the immunization system database. VE was calculated with conditional logistic regression according to the formula (1–OR) ×100%.Results: Overall, 603 adults aged 60 years or older with pneumococcal disease and positive for Streptococcus pneumoniae were included as cases, and 19.6% (118 persons) had a recorded PPV23 vaccination. The controls included 1,206 adults, whose vaccination rate was 23.8% (287 persons). The VE against pneumococcal diseases among the whole population was 24% (95% CI: 2%, 40%) and among women 44% (95% CI: 6%, 67%). After adjusting for multiple variables, the effectiveness of PPV23 against pneumococcal diseases was still statistically significant with VE for all of 25% (95% CI: 3%, 42%) and VE for women of 49% (95% CI: 11%, 71%).Conclusion: PPV23 was effective against pneumococcal diseases in adults aged 60 years or older in Shanghai, China. Its relatively high effectiveness among women warrants this group to be particularly targeted for vaccination, with further research on why vaccination effectiveness is less among men.

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Effectiveness of Covishield vaccine in preventing Covid–19 — A test–negative case–control study

10.1101/2021.07.19.21260693 ◽

2021 ◽

Author(s):

Stuti Pramod ◽

Dhanajayan Govindan ◽

Premkumar Ramasubramani ◽

Sitanshu Sekhar Kar ◽

Rakesh Aggarwal ◽

...

Keyword(s):

Conditional Logistic Regression ◽

Severe Disease ◽

Case Control ◽

Vaccine Effectiveness ◽

Separate Analysis ◽

Occupational Role ◽

Negative Case ◽

Protection Rate ◽

Using Data ◽

Control Study

Introduction: This study was aimed at assessing the vaccine effectiveness (VE) of Covishield, which is identical to the AstraZeneca vaccine, in preventing laboratory–confirmed Covid–19. Methods: Using a test–negative case–control design, information on vaccination status of cases with Covid–19 among healthcare workers in our institution in Puducherry, India, and an equal number of matched controls, i.e. positive and negative for SARS–CoV–2 by RT–PCR, was obtained. The cases and controls were matched for age (± 3 years) and date of testing (± 3 days). The groups were compared using multivariable conditional logistic regression to calculate odds ratios (OR), with adjustment for gender, occupational role, presence of symptoms and presence of a comorbidity condition. Per cent vaccine effectiveness (VE) was calculated as 100×(1−adjusted odds ratio). Results: Using data from 360 case–control pairs, VE of one dose and of two doses, in providing protection against Covid–19 was 49% (95% CI: 17%–68%) and 54% (27%–71%), respectively. In view of a difference in the proportion of cases and controls who had symptoms, a separate analysis of data from 203 pairs where both the case and the control had symptoms was done, which showed, VE of 58% (28%–75%) and 64% (38%–78%) after one dose and two doses, respectively. Among cases with moderately severe disease that required oxygen therapy, VE following any number of vaccine doses was 95% (44%–100%). Conclusion: Covishield vaccine protected significantly against Covid–19, with the protection after two doses being slightly higher than after one dose, and a particularly high protection rate against severe forms of the disease. Keywords: Covishield, Vaccine effectiveness, Test–negative design

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Investigation of Vaccine Breakthrough Infections by Vaccine strategy during the Delta Variant Wave in France

10.1101/2021.12.05.21267301 ◽

2021 ◽

Author(s):

Antonin Bal ◽

Grégory Destras ◽

Bruno Simon ◽

Jean-Marc Giannoli ◽

Florence Morfin ◽

...

Keyword(s):

Single Dose ◽

Young Patients ◽

Positive Test ◽

Rt Pcr ◽

Vaccine Strategy ◽

Delta Wave ◽

Vaccine Schedule ◽

High Prevalence ◽

Full Immunization

AbstractHerein, we describe the characteristics of vaccine breakthrough infections (VBI) in fully vaccinated individuals according to five vaccine strategies during the Delta wave in France. Inclusion criterion was a positive test at least 2 weeks after a full vaccine schedule: homologous vaccination with Pfizer-BioNTech (BNT162b2) or Moderna (mRNA-1273); heterologous vaccination with Astrazeneca and Pfizer-BioNTech (ChadOx1/BNT162b2); single-dose vaccines Johnson & Johnson (Ad26.COV2.S) or Astrazeneca (ChadOx1). A total of 1630 VBI from patients fully vaccinated between February and July were included in this study. SARS-CoV-2 sequencing performed for 1366 samples showed that the delta variant represented 94.1% (1286/1366). Delta-VBI were mainly symptomatic (mild symptoms) with no difference according to the vaccine strategy (p=0.362). The median RT-PCR Ct values at diagnosis were significantly different between symptomatic and asymptomatic cases only for BNT162b2 group (17.7 (15.07, 20.51) vs 19.00 (16.00, 23.00), p=0.004). Up to 50% of VBI was classified as early-VBI (infected less than one month after full immunization) for BNT162b2, mRNA-1273, ChadOx1, and J Ad26.COV2.S. People aged 14-49 yo were overrepresented in early VBI compared to non-early VBI for BNT162b2 and mRNA-1273 (73.92% vs 37.87% for BNT162b2 and 77.78% vs 46.67 % for mRNA-1273, p<0.05). Our data emphasize a high prevalence of Delta-VBI occurring only one month after full immunization in young patients that might be related to relaxation of barrier gestures.

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