An observational cohort study on the incidence of SARS-CoV-2 infection and B.1.1.7 variant infection in healthcare workers by antibody and vaccination status

AbstractBackgroundNatural and vaccine-induced immunity will play a key role in controlling the SARS-CoV-2 pandemic. SARS-CoV-2 variants have the potential to evade natural and vaccine-induced immunity.MethodsIn a longitudinal cohort study of healthcare workers (HCWs) in Oxfordshire, UK, we investigated the protection from symptomatic and asymptomatic PCR-confirmed SARS-CoV-2 infection conferred by vaccination (Pfizer-BioNTech BNT162b2, Oxford-AstraZeneca ChAdOx1 nCOV-19) and prior infection (determined using anti-spike antibody status), using Poisson regression adjusted for age, sex, temporal changes in incidence and role. We estimated protection conferred after one versus two vaccinations and from infections with the B.1.1.7 variant identified using whole genome sequencing.Results13,109 HCWs participated; 8285 received the Pfizer-BioNTech vaccine (1407 two doses) and 2738 the Oxford-AstraZeneca vaccine (49 two doses). Compared to unvaccinated seronegative HCWs, natural immunity and two vaccination doses provided similar protection against symptomatic infection: no HCW vaccinated twice had symptomatic infection, and incidence was 98% lower in seropositive HCWs (adjusted incidence rate ratio 0.02 [95%CI <0.01-0.18]). Two vaccine doses or seropositivity reduced the incidence of any PCR-positive result with or without symptoms by 90% (0.10 [0.02-0.38]) and 85% (0.15 [0.08-0.26]) respectively. Single-dose vaccination reduced the incidence of symptomatic infection by 67% (0.33 [0.21-0.52]) and any PCR-positive result by 64% (0.36 [0.26-0.50]). There was no evidence of differences in immunity induced by natural infection and vaccination for infections with S-gene target failure and B.1.1.7.ConclusionNatural infection resulting in detectable anti-spike antibodies and two vaccine doses both provide robust protection against SARS-CoV-2 infection, including against the B.1.1.7 variant.SummaryNatural infection resulting in detectable anti-spike antibodies and two vaccine doses both provided ≥ 85% protection against symptomatic and asymptomatic SARS-CoV-2 infection in healthcare workers, including against the B.1.1.7 variant. Single dose vaccination reduced symptomatic infection by 67%.

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Hybrid immunity versus vaccine-induced immunity against SARS CoV2 in Patients with Autoimmune Rheumatic Diseases

10.1101/2021.08.26.21258418 ◽

2021 ◽

Cited By ~ 1

Author(s):

Padmanabha Shenoy ◽

Sakir Ahmed ◽

Aby Paul ◽

Somy Cherian ◽

Rashwith Umesh ◽

...

Keyword(s):

Single Dose ◽

Rheumatic Diseases ◽

Natural Infection ◽

Double Dose ◽

Immune Protection ◽

Neutralization Potential ◽

Vaccine Responses ◽

Autoimmune Rheumatic Diseases ◽

Induced Immunity ◽

Dose Vaccine

AbstractIntroductionSingle-dose COVID-19 vaccines in healthy individuals with past COVID-19 infections seem to provide better immunity than double doses in COVID-19 unexposed individuals. However, it is not known whether the same is true for patients with autoimmune rheumatic diseases (AIRD) who are on immunosuppressants.MethodsWe identified 30 patients with AIRD who took a single dose of the ChAdOx1 vaccine post-COVID-19 infection. Age, sex and disease similar patients were enrolled in to three groups of 30 each who had (1) past infection with COVID-19 but no vaccine, (2) a single dose of ChAdOx1 and (3) double doses of ChAdOx1. Sera were collected from each patient approximately 30 days after last vaccine dose or since the onset of COVID19 symptoms (in the unvaccinated group). Antibodies to spike protein were estimated and virus neutralization potential of sera was tested.ResultsBaseline characteristics including drug usage was similar betweenthe groups. Seroconversion occurred in 25(83%), 23(77%), 27(90%), and 30(100%) in natural infection, single-dose vaccine, double dose vaccine, and infection +single dose vaccine groups respectively. Mean antibody titres (10076.8±8998) in the last group were at least 6-100x higher than in the other 3 groups. Also, the infection +vaccine group had the highest neutralization potential of 83.37 % as compared to 45.4% in the fully vaccinated group.ConclusionThe hybrid immunity with a single dose of the vector-based vaccine post-infection seems to be superior to double dosage of the vaccine in patients with AIRD. A universal vaccination strategy involving a single dose of vaccine for all individuals with previous COVID-19 infection seems to be effective in these patients also.What is already known about this subject?A single dose of an RNA based COVID-19 vaccine after COVID-19 natural infection provides superior immune protection as compared to double doses of vaccines in infection naïve personsA second dose of vaccine in healthy people who had infection previously does not increase the immune protection but may paradoxically induce toleranceVaccine responses in patients with autoimmune rheumatic diseases(AIRD) may be suboptimal due to underlying disease or the use of immunosuppressants.What does this study add?Hybrid-induced immunity (single vaccine post COVID-19 infection) produces adequate vaccine responses in patients with AIRD, non-inferior to double dose of vaccineBesides mRNA vaccines, the adenoviral vector vaccine AZD1222 also demonstrates this hybrid phenomenon.How might this impact on clinical practice?Vaccination policies can consider providing only a single vaccine in those who had previous COVID-19 infection. This strategy has been shown not to be harmful for patients with AIRD. This will help reduce vaccine shortages.

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Immune responses to cholera following natural infection: a review

10.1101/2020.07.27.20163139 ◽

2020 ◽

Author(s):

Tiffany Leung ◽

Laura Matrajt

Keyword(s):

Diarrheal Disease ◽

Clinical Symptoms ◽

Natural Infection ◽

Small Sample ◽

Natural Immunity ◽

Symptomatic Infection ◽

Correlates Of Protection ◽

Serological Studies ◽

Small Sample Sizes ◽

One Year

Cholera is an acute, diarrheal disease caused by Vibrio cholerae O1 or 139 that is associated with a high global burden. While it is accepted that natural immunity against cholera infection exists, no clear correlate of protection has been identified. In this review, we identify the estimated duration of immunity following cholera infection with and without clinical symptoms from available published studies. We searched Pubmed and Web of Science for studies examining the long-term infection-acquired immunity against cholera infection. We identified 22 eligible studies that included individuals residing primarily in Bangladesh and North America. % We observed the duration of immunity is estimated to last the longest in observational studies than in challenge studies, with serologic evidence of various potential correlates of protection becoming undetectable by one year. Although with small sample sizes, three studies found that most participants with a subclinical infection from an initial challenge with cholera had a symptomatic infection when rechallenged with a homologous biotype, suggesting that a subclinical cholera infection may confer lower protection than a clinical one. We identified the longest duration of immunity recorded by observational and challenge studies to be three years, but all the serological studies showed that various potential correlates of protection became undetectable by one year.

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Weak Cross-Lineage Neutralization by Anti SARS-CoV-2 Spike Antibodies after Natural Infection or Vaccination Is Rescued by Repeated Immunological Stimulation

Vaccines ◽

10.3390/vaccines9101124 ◽

2021 ◽

Vol 9 (10) ◽

pp. 1124

Author(s):

Sara Caucci ◽

Benedetta Corvaro ◽

Sofia Maria Luigia Tiano ◽

Anna Valenza ◽

Roberta Longo ◽

...

Keyword(s):

Single Dose ◽

Natural Infection ◽

Neutralizing Antibody ◽

Natural Immunity ◽

Anamnestic Response ◽

Neutralizing Activity ◽

Immunological Markers ◽

The Cross ◽

One Year

After over one year of evolution, through billions of infections in humans, SARS-CoV-2 has evolved into a score of slightly divergent lineages. A few different amino acids in the spike proteins of these lineages can hamper both natural immunity against reinfection, and vaccine efficacy. In this study, the in vitro neutralizing potency of sera from convalescent COVID-19 patients and vaccinated subjects was analyzed against six different SARS-CoV-2 lineages, including the latest B.1.617.2 (or Delta variant), in order to assess the cross-neutralization by anti-spike antibodies. After both single dose vaccination, or natural infection, the neutralizing activity was low and fully effective only against the original lineage, while a double dose or a single dose of vaccine, even one year after natural infection, boosted the cross-neutralizing activity against different lineages. Neither binding, nor the neutralizing activity of sera after vaccination, could predict vaccine failure, underlining the need for additional immunological markers. This study points at the importance of the anamnestic response and repeated vaccine stimulations to elicit a reasonable cross-lineage neutralizing antibody response.

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COVID-19 vaccine effectiveness among healthcare workers in Portugal: results from a hospital-based cohort study, December 2020 to November 2021

10.1101/2022.01.07.22268889 ◽

2022 ◽

Author(s):

Vânia Gaio ◽

Adriana Silva ◽

Palmira Amaral ◽

João Faro Viana ◽

Pedro Pinto Leite ◽

...

Keyword(s):

Cohort Study ◽

Healthcare Workers ◽

Vaccine Effectiveness ◽

Symptomatic Infection ◽

Cox Models ◽

Mainland Portugal ◽

Hazard Ratios ◽

Group Sex ◽

Tagus Valley

Introduction: Healthcare workers (HCW) were amongst the first prioritized for COVID-19 vaccination but data on COVID–19 vaccine effectiveness among HCW is still limited. This study aims to estimate the COVID–19 vaccine effectiveness (VE) against SARS–CoV–2 symptomatic infection among HCW from Portuguese hospitals. Methods: In this prospective cohort study, we analysed data from HCW (all professional categories) from two central hospitals in the Lisbon and Tagus Valley and Centre regions of mainland Portugal between December 2020 and November 2021. VE against symptomatic SARS–CoV–2 infection was estimated as one minus the confounder adjusted hazard ratios by Cox models considering age group, sex, presence of chronic disease and occupational exposure to patients diagnosed with COVID–19 as adjustment variables. Results: During the 11 months of follow up, the 2213 HCW contributed a total of 1950 person-years at risk and 171 SARS–CoV–2 events occurred. The COVID–19 incidence rate for unvaccinated HCW was 348.7 per 1000 person-years while for fully vaccinated HCW was 43.0 per 1000 person-years. We observed a VE against symptomatic SARS–CoV–2 infection of 73.9% (95% CI: 26.2–90.8%) for complete vaccination status. Conclusion: This cohort study found a high COVID-19 VE against symptomatic SARS–CoV–2 infection in Portuguese HCW, which is in concordance with previous studies from other countries. Monitoring of VE in this HCW cohort continues during the winter 2021/2022 to evaluate potential VE decay and booster vaccine effect. Keywords: Vaccine effectiveness, SARS–CoV–2 , COVID–19, symptomatic infection, healthcare workers.

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IgA and IgG antibodies in SARS-CoV-2 vaccinated health workers by a homemade ELISA diagnostic test

The EuroBiotech Journal ◽

10.2478/ebtj-2021-0016 ◽

2021 ◽

Vol 5 (s1) ◽

pp. 13-19

Author(s):

Tagliaferro Luigi ◽

Menegazzi Paola ◽

Cossa Luca Giulio ◽

Maffia Michele

Keyword(s):

Serum Sample ◽

Healthcare Workers ◽

Vaccine Development ◽

Health Workers ◽

Elisa Test ◽

Natural Immunity ◽

Igg Antibodies ◽

Serum Samples ◽

Three Samples ◽

Induced Immunity

Abstract The SARS-CoV-2 pandemic has accelerated vaccine development and testing, an important step in its eradication. Health workers were included among the first subjects to be vaccinated, therefore it was necessary to check their immunological status after the first and second dose of vaccine. Serum samples belonging to 24 health workers undergoing vaccination for SARS-CoV-2 (Pfizer-BioNTech) were analysed: for 2 of them it was also possible to obtain a serum sample prior to the first dose of vaccine (zero time); antibody dosing was performed in 18 out of 24 after the first and second vaccination dose; in the remaining 6 healthcare workers a serum sample was obtained only after the second dose. In each serum sample, IgA and IgG antibodies to "Spike Receptor Binding Domain" (RBD) and "Nucleocapsid" (N) proteins were searched by ELISA test. Except for the two subjects for whom it was possible to have a serum sample before vaccination, the others were collected on day 18 from the first dose of vaccine and on day 8 from the second dose. Serum samples collected after the first dose of vaccine showed reactivity to anti-RBD IgG in 11 out of 18 healthcare workers and to IgA in 2 subjects. After the second dose all 24 samples showed the presence of anti-S IgG, while 5 revealed a reactivity for anti-S IgA. Three samples showed reactivity towards anti-N IgG. The ELISA test has shown all its effectiveness in controlling post vaccine immunity and in discriminating natural immunity from vaccine induced immunity.

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The risk of symptomatic reinfection during the second COVID-19 wave in individuals previously exposed to SARS-CoV-2

10.1101/2021.04.14.21255502 ◽

2021 ◽

Author(s):

Mattia Manica ◽

Serena Pancheri ◽

Piero Poletti ◽

Giulia Giovanazzi ◽

Giorgio Guzzetta ◽

...

Keyword(s):

Cohort Study ◽

Cumulative Incidence ◽

Protective Immunity ◽

Natural Infection ◽

Entire Population ◽

Serological Response ◽

Igg Antibodies ◽

Symptomatic Infection

To what extent infection with SARS-CoV-2 protects against subsequent reinfection or symptomatic reinfection is still unclear. In this cohort study, we analyzed surveillance records of COVID-19 cases identified between June 2020 and January 2021 in five Italian municipalities, where 77.7% of the entire population was screened for IgG antibodies in May 2020. We compared the risk of observing symptomatic infections in two mutually exclusive groups defined by the initial serological response. We estimated that the cumulative incidence of identified symptomatic infections in the IgG negative and positive cohorts was 2.67% (95%CI: 2.12%-3.37%) and 0.14% (95%CI: 0.04%-0.58%), respectively. The adjusted odd ratio of developing symptomatic infection in individuals previously exposed to SARS-CoV-2 was estimated at 0.054 (95%CI: 0.009-0.169). Quantifying protective immunity against COVID-19 disease elicited by natural infection with SARS-CoV-2 is essential to inform strategies for controlling the pandemic in the forthcoming months.

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Effectiveness of BNT162b2 COVID-19 Vaccine in Preventing Severe Symptomatic Infection among Healthcare Workers

Medicina ◽

10.3390/medicina57080746 ◽

2021 ◽

Vol 57 (8) ◽

pp. 746

Author(s):

Efrén Murillo-Zamora ◽

Xóchitl Trujillo ◽

Miguel Huerta ◽

Mónica Riós-Silva ◽

Oliver Mendoza-Cano

Keyword(s):

Cohort Study ◽

Real World ◽

Healthcare Workers ◽

Severe Illness ◽

Single Shot ◽

Symptomatic Infection ◽

Cross Sectional ◽

Working Age ◽

Study Population ◽

Sectional Analysis

Background and Objectives: This study aims to evaluate the effectiveness of the BNT162b2 COVID-19 (coronavirus disease 2019) in preventing severe symptomatic laboratory-confirmed infection among healthcare workers in a real-world scenario. Materials and Methods: A cross-sectional analysis of a prospective cohort study was conducted. Subjects with onset illness from January to February 2021 were eligible and classified according to the number of vaccine doses received (single-shot, n = 8; two-shot, n = 12; unvaccinated, n = 290). Results: The vaccine effectiveness against severe illness was 100% in the single and two-shot group. The presented results suggest that vaccination reduces the frequency of severe symptomatic COVID-19 in working-age adults. Conclusions: Efforts focusing on maximizing the number of immunized subjects in the study population may reduce associated economic and social burdens.

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The future of vaccination and herd immunity in the COVID-19 pandem-ic

MEDISAINS ◽

10.30595/medisains.v19i2.11661 ◽

2021 ◽

Vol 19 (2) ◽

pp. 25

Author(s):

Supriyadi Supriyadi

Keyword(s):

Single Dose ◽

Cellular Immunity ◽

Herd Immunity ◽

Natural Immunity ◽

Humoral And Cellular Immunity ◽

Duration Of Protection ◽

Hybrid Distribution ◽

And Control ◽

Induced Immunity ◽

The Ideal

Since a year ago, pandemic covid 19 has entered Indonesia, and efforts to reduce and control have been carried out several programs, one of which is vaccination. The ideal projection is two direct strategies: hybrid distribution that combines active outreach into priority groups with passive distribution to the general public and single-dose distribution to as many populations as possible. The previous plan was to save a second dose as a backup. The proper fulfillment of vaccination needs in each population required to achieve herd immunity to stop the spread of the virus will vary, depending on the variant of the virus in circulation and the heterogeneous level of that population, also depending on the density and mobility of the population. In addition, the duration of protection provided by natural immunity and vaccine-induced immunity is not well established, and different vaccines can provide different durations and degrees of humoral and cellular immunity.

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Impact of Delta on viral burden and vaccine effectiveness against new SARS-CoV-2 infections in the UK

10.1101/2021.08.18.21262237 ◽

2021 ◽

Cited By ~ 25

Author(s):

Koen B. Pouwels ◽

Emma Pritchard ◽

Philippa C. Matthews ◽

Nicole Stoesser ◽

David W. Eyre ◽

...

Keyword(s):

Single Dose ◽

Natural Infection ◽

Community Based ◽

Symptomatic Infection ◽

Younger Adults ◽

Dosing Interval ◽

Viral Burden ◽

The Uk ◽

Prior Infection ◽

Similar Peak

AbstractThe effectiveness of BNT162b2, ChAdOx1, and mRNA-1273 vaccines against new SARS-CoV-2 infections requires continuous re-evaluation, given the increasingly dominant Delta variant. We investigated the effectiveness of the vaccines in a large community-based survey of randomly selected households across the UK. We found that the effectiveness of BNT162b2 and ChAd0x1 against any infections (new PCR positives) and infections with symptoms or high viral burden is reduced with the Delta variant. A single dose of the mRNA-1273 vaccine had similar or greater effectiveness compared to a single dose of BNT162b2 or ChAdOx1. Effectiveness of two doses remains at least as great as protection afforded by prior natural infection. The dynamics of immunity following second doses differed significantly between BNT162b2 and ChAdOx1, with greater initial effectiveness against new PCR-positives but faster declines in protection against high viral burden and symptomatic infection with BNT162b2. There was no evidence that effectiveness varied by dosing interval, but protection was higher among those vaccinated following a prior infection and younger adults. With Delta, infections occurring following two vaccinations had similar peak viral burden to those in unvaccinated individuals. SARS-CoV-2 vaccination still reduces new infections, but effectiveness and attenuation of peak viral burden are reduced with Delta.

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Correlates of Neutralization Against SARS-CoV-2 Variants of Concern by Early Pandemic Sera

Journal of Virology ◽

10.1128/jvi.00404-21 ◽

2021 ◽

Author(s):

Samuel J. Vidal ◽

Ai-ris Y. Collier ◽

Jingyou Yu ◽

Katherine McMahan ◽

Lisa H. Tostanoski ◽

...

Keyword(s):

Natural Infection ◽

Neutralizing Antibody ◽

Natural Immunity ◽

Spike Gene ◽

Cell Responses ◽

Fold Reduction ◽

Cross Neutralization ◽

Protection Against Infection ◽

Induced Immunity ◽

Shed Light

Emerging SARS-CoV-2 variants of concern that overcome natural and vaccine-induced immunity threaten to exacerbate the COVID-19 pandemic. Increasing evidence suggests that neutralizing antibody (NAb) responses are a primary mechanism of protection against infection. However, little is known about the extent and mechanisms by which natural immunity acquired during the early COVID-19 pandemic confers cross-neutralization of emerging variants. In this study, we investigated cross-neutralization of the B.1.1.7 and B.1.351 SARS-CoV-2 variants in a well-characterized cohort of early pandemic convalescent subjects. We observed modestly decreased cross-neutralization of B.1.1.7 but a substantial 4.8-fold reduction in cross-neutralization of B.1.351. Correlates of cross-neutralization included receptor binding domain (RBD) and N-terminal domain (NTD) binding antibodies, homologous NAb titers, and Membrane-directed T cell responses. These data shed light on cross-neutralization of emerging variants by early pandemic convalescent immune responses. IMPORTANCE Widespread immunity to SARS-CoV-2 will be necessary to end the COVID-19 pandemic. Neutralizing antibody (NAb) responses are a critical component of immunity that can be stimulated by natural infection as well as vaccines. However, SARS-CoV-2 variants are emerging that contain mutations in the Spike gene that promote evasion from NAb responses. These variants may therefore delay control of the COVID-19 pandemic. We studied whether NAb responses from early COVID-19 convalescent patients are effective against the two SARS-CoV-2 variants B.1.1.7 and B.1.351. We observed that the B.1.351 variant demonstrates significantly reduced susceptibility to early pandemic NAb responses. We additionally characterized virologic, immunologic, and clinical features that correlate with cross-neutralization. These studies increase our understanding of emerging SARS-CoV-2 variants.

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