Risk of SARS-CoV-2 reinfections in children: a prospective national surveillance study between January, 2020, and July, 2021, in England [Scholarly Article - The Lancet, March 2022]

Title:

Risk of SARS-CoV-2 reinfections in children: a prospective national surveillance study between January, 2020, and July, 2021, in England

 

Authors:

Anna A Mensah, MSc; Helen Campbell, PhD;  Julia Stowe, PhD; Giulia Seghezzo, MSc; Ruth Simmons, PhD; Joanne Lacy, MSc; Antoaneta Bukasa, MSc; Shennae O'Boyle, MSc; Mary E Ramsay, FFPH; Kevin Brown, FRCPath & Shamez N Ladhani, PhD

 

Published:

The Lancet, 28 March 2022 (Open Access)

https://www.thelancet.com/journals/lanchi/article/PIIS2352-4642(22)00059-1/fulltext

 

Summary

Background

Background Reinfection after primary SARS-CoV-2 infection is uncommon in adults, but little is known about the risks, characteristics, severity, or outcomes of reinfection in children. We aimed to assess the risk of SARS-CoV-2 reinfection in children and compare this with the risk in adults, by analysis of national testing data for England.

Vaccine effectiveness against SARS-CoV-2 infection with the Omicron or Delta variants following a two-dose or booster BNT162b2 or mRNA-1273 vaccination series: A Danish cohort study [Preprint - medRxiv, December 2021]

Title:

Vaccine effectiveness against SARS-CoV-2 infection with the Omicron or Delta variants following a two-dose or booster BNT162b2 or mRNA-1273 vaccination series: A Danish cohort study  

 

Authors:

Christian Holm Hansen, Astrid Blicher Schelde, Ida Rask Moustsen-Helm, Hanne-Dorthe Emborg, Tyra Grove Krause, Kåre Mølbak & Palle Valentiner-Branth

 

Published:

medRxiv, 21 December 2021

https://www.medrxiv.org/content/10.1101/2021.12.20.21267966v1

 

Note: 

This article is a preprint and has not been peer-reviewed. 

 

Abstract:

In this brief communication we are showing original research results with early estimates from Danish nationwide databases of vaccine effectiveness (VE) against the novel SARS-CoV-2 Omicron variant (B.1.1.529) up to five months after a primary vaccination series with the BNT162b2 or mRNA-1273 -19 vaccines.  Our study provides evidence of protection against infection with the Omicron variant after completion of a primary vaccination series with the BNT162b2 or mRNA-1273 vaccines; in particular, we found a VE against the Omicron variant of 55.2% (95% confidence interval (CI): 23.5 to 73.7%) and 36.7% (95% CI: 69.9 to 76.4%) for the BNT162b2 and mRNA-1273 vaccines, respectively, in the first month after primary vaccination. However, the VE is significantly lower than that against Delta infection and declines rapidly over just a few months. The VE is re-established upon revaccination with the BNT162b2 vaccine (54.6%, 95% CI: 30.4 to 70.4%).

Signature of long-lived memory CD8+ T cells in acute SARS-CoV-2 infection [Preprint - Nature, December 2021]

Title:

Signature of long-lived memory CD8+ T cells in acute SARS-CoV-2 infection 

 

Authors:

Sarah Adamo, Jan Michler, Yves Zurbuchen, Carlo Cervia, Patrick Taeschler, Miro E. Raeber, Simona Baghai Sain, Jakob Nilsson, Andreas E. Moor & Onur Boyman  

 

Published:

Nature, 7 December 2021

https://www.nature.com/articles/s41586-021-04280-x

[Note: This is a preprint and not yet peer reviewed]

 

Abstract:

We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.  Abstract Immunological memory is a hallmark of adaptive immunity and facilitates an accelerated and enhanced immune response upon re-infection with the same pathogen1,2. Since the outbreak of the ongoing coronavirus disease 19 (COVID-19) pandemic, a key question has focused on which severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cells stimulated during acute infection give rise to long-lived memory T cells3. Using spectral flow cytometry combined with cellular indexing of transcriptomes and T cell receptor (TCR) sequencing we longitudinally characterize individual SARS-CoV-2-specific CD8+ T cells of COVID-19 patients from acute infection to one year into recovery and find a distinct signature identifying long-lived memory CD8+ T cells. SARS-CoV-2-specific memory CD8+ T cells persisting one year after acute infection express CD45RA, interleukin-7 receptor α (CD127), and T cell factor-1 (TCF1), but they maintain low CCR7, thus resembling CD45RA+ effector-memory T (TEMRA) cells. Tracking individual clones of SARS-CoV-2-specific CD8+ T cells, we reveal that an interferon signature marks clones giving rise to long-lived cells, whereas prolonged proliferation and mammalian target of rapamycin (mTOR) signaling are associated with clonal disappearance from the blood. Collectively, we describe a transcriptional signature that marks long-lived, circulating human memory CD8+ T cells following an acute virus infection.

 

SARS-CoV-2 spike protein as a bacterial lipopolysaccharide delivery system in an overzealous inflammatory cascade [Preprint - bioRxiv, 29 October 2021]

Title:

SARS-CoV-2 spike protein as a bacterial lipopolysaccharide delivery system in an overzealous inflammatory cascade 

 

Authors:

Firdaus Samsudin, Palur Raghuvamsi, Ganna Petruk, Manoj Puthia, Jitka Petrlova, Paul MacAry, Ganesh S. Anand, Artur Schmidtchen & Peter J. Bond

Published:

bioRxiv, 29 October 2021

https://www.biorxiv.org/content/10.1101/2021.10.29.466401v1

[This article is a preprint and has not been certified by peer review.]

 

Abstract:

Accumulating evidence indicates a potential role for bacterial lipopolysaccharide (LPS) in the overactivation of the immune response during SARS-CoV-2 infection. LPS is recognised by Toll-like receptor 4 (TLR4) in innate immunity. Here, we showed that LPS binds to multiple hydrophobic pockets spanning both the S1 and S2 subunits of the SARS-CoV-2 spike (S) protein. LPS binds to the S2 pocket with a lower affinity compared to S1, suggesting its possible role as an intermediate in the TLR4 cascade. Congruently, nuclear factor-kappa B (NF-κB) activation in vitro is strongly boosted by S2. In vivo, however, a boosting effect is observed for both S1 and S2, with the former potentially facilitated by proteolysis. Collectively, our study suggests the S protein may act as a delivery system for LPS in host innate immune pathways. The LPS binding pockets are highly conserved across different SARS-CoV-2 variants and therefore represent potential therapeutic targets.

COVID-19 deaths detected in a systematic post-mortem surveillance study in Africa [Preprint - medRxiv, 24 December 2020]

Title:

COVID-19 deaths detected in a systematic post-mortem surveillance study in Africa

 

Authors:

Lawrence Mwananyanda, Christopher J. Gill, William MacLeod, Geoffrey Kwenda, Rachel Pieciak, Zachariah Mupila, Francis Mupeta, Leah Forman, Luunga Ziko, Lauren Etter & Donald Thea

 

Published:

medRxiv, 24 December 2020

[This article is a preprint and has not been peer-reviewed.]

https://www.medrxiv.org/content/10.1101/2020.12.22.20248327v1

 

Abstract:

Objectives 

Limited SARS CoV 2 testing in many African countries has constrained availability of data on the impact of COVID-19 (CV19). To address this gap, we conducted a systematic post-mortem surveillance study to directly measure the fatal impact of CV19 in an urban African population.  

 

Design 

We enrolled deceased individuals at the University Teaching Hospital (UTH) Morgue in Lusaka, Zambia. We obtained nasopharyngeal swabs for testing via reverse-transcriptase quantitative PCR (RT-qPCR) against the SARS-2 Coronavirus. We stratified deaths by CV19 status, by location, age, sex, and underlying risk factors.  

 

Setting 

UTH is Zambia’s largest tertiary care referral hospital and its morgue registers ∼80% of Lusaka’s deaths.  

 

Participants 

Participants of all ages were enrolled if within 48 hours of death and if the next of kin or representative provided written informed consent.  

 

Results 

We enrolled 372 participants between June and September 2020, and had PCR results for 364 (99.5%). CV19 was detected in 70/364 (19.2%). The median age for CV19+ deaths was 48 years (IQR 36-72 years) and 70% were male. Most CV19+ deaths (51/70, 72.8%) occurred in the community; none had been tested for CV19 antemortem. Among the 19/70 facility deaths, six were tested antemortem. Among the 52/70 CV19 deaths with symptoms data, 44/52 had typical symptoms of CV19 (cough, fever, shortness of breath), of whom only five were tested antemortem. We identified CV19 among seven children; only one had been tested antemortem. The proportion of CV19+ deaths increased with age, but 75.7% of CV19+ deaths were aged <60 years. The five most common co-morbidities among CV19+ deaths were: tuberculosis (31.4%); hypertension (27.1%); HIV/AIDS (22.9%); alcohol use (17.1%); and diabetes (12.9%).  

 

Conclusions 

Contrary to expectations, CV19+ deaths were common in Lusaka. The majority occurred in the community where testing capacity is lacking. Yet few who died at facilities were tested, despite presenting with typical symptoms of CV19. Therefore, CV19 cases were under reported because testing was rarely done, not because CV19 was rare. If our data are generalizable, the impact of CV19 in Africa has been vastly underestimated.

Landmark Danish study finds no significant effect for facemask wearers by Prof Carl Heneghan & Tom Jefferson

Title:

Landmark Danish study finds no significant effect for facemask wearers

 

Authors:

Prof Carl Heneghan & Tom Jefferson

[Both from the University of Oxford]

 

Published:

The Spectator, 19 November 2020

https://www.spectator.co.uk/article/do-masks-stop-the-spread-of-covid-19-

 

From the article:

Do face masks work? Earlier this year, the UK government decided that masks could play a significant role in stopping Covid-19 and made masks mandatory in a number of public places. But are these policies backed by the scientific evidence?  

 

Yesterday marked the publication of a long-delayed trial in Denmark which hopes to answer that very question. The ‘Danmask-19 trial’ was conducted in the spring with over 6,000 participants, when the public were not being told to wear masks but other public health measures were in place. Unlike other studies looking at masks, the Danmask study was a randomised controlled trial – making it the highest quality scientific evidence.

medRxiv, 5 November 2020 (preprint) - An international survey on the impact of COVID-19 in individuals with Down syndrome

Title:

An international survey on the impact of COVID-19 in individuals with Down syndrome   

 

Authors:

Anke Hüls, Alberto C. S. Costa, Mara Dierssen, R. Asaad Baksh, Stefania Bargagna, Nicole T. Baumer, Ana Claudia Brandão, Angelo Carfi, Maria Carmona-Iragui, Brain Allen Chicoine, Sujay Ghosh, Monica Lakhanpaul, Coral Manso, Miguel-Angel Mayer, Maria del Carmen Ortega, Diego Real de Asua, Anne-Sophie Rebillat, Lauren Ashley Russell, Giuseppina Sgandurra, Diletta Valentini, Stephanie L Sherman & Andre Strydom

 

Published:

medRxiv, 5 November 2020

[Keep in mind that this article is a preprint and not yet peer reviewed.]

https://www.medrxiv.org/content/10.1101/2020.11.03.20225359v1

 

Abstract:

Background: 

Health conditions and immune dysfunction associated with trisomy 21 (Down syndrome, DS) may impact the clinical course of COVID-19 once infected by SARS-CoV-2.  

 

Methods: 

The T21RS COVID-19 Initiative launched an international survey for clinicians or caregivers/family members on patients with COVID-19 and DS (N=1046). De-identified survey data collected between April and October 2020 were analysed and compared with the UK ISARIC4C survey of hospitalized COVID-19 patients with and without DS. COVID-19 patients with DS from the ISARIC4C survey (ISARIC4C DS cases=100) were matched to a random set of patients without DS (ISARIC4C controls=400) and hospitalized DS cases in the T21RS survey (T21RS DS cases=100) based on age, gender, and ethnicity.  

 

Finding:

The mean age in the T21RS survey was 29 years (SD=18), 73% lived with their family. Similar to the general population, the most frequent signs and symptoms of COVID-19 were fever, cough, and shortness of breath. Pain and nausea were reported less frequently (p<0.01), whereas altered consciousness/confusion were reported more frequently (p<0.01). Risk factors for hospitalization and mortality were similar to the general population (age, male gender, diabetes, obesity, dementia) with the addition of congenital heart defects as a risk factor for hospitalization. Mortality rates showed a rapid increase from age 40 and were higher than for controls (T21RS DS versus controls: risk ratio (RR)=3.5 (95%-CI=2.6;4.4), ISARIC4C DS versus controls: RR=2.9 (95%-CI=2.1;3.8)) even after adjusting for known risk factors for COVID-19 mortality.  

 

Interpretation:

Leading signs/symptoms of COVID-19 and risk factors for severe disease course are similar to the general population. However, individuals with DS present significantly higher rates of mortality, especially from age 40.

 

Science, 28 October 2020 - Robust neutralizing antibodies to SARS-CoV-2 infection persist for months

Title:

Robust neutralizing antibodies to SARS-CoV-2 infection persist for months

 

Authors:

Ania Wajnberg, Fatima Amanat, Adolfo Firpo, Deena R. Altman, Mark J. Bailey, Mayce Mansour, Meagan McMahon, Philip Meade, Damodara Rao Mendu, Kimberly Muellers, Daniel Stadlbauer, Kimberly Stone, Shirin Strohmeier, Viviana Simon, Judith Aberg, David L. Reich, Florian Krammer & Carlos Cordon-Cardo

 

Published:  

Science, 28 October 2020

https://science.sciencemag.org/content/early/2020/10/27/science.abd7728?rss=1

Abstract:

SARS-CoV-2 has caused a global pandemic with millions infected and numerous fatalities. Questions regarding the robustness, functionality, and longevity of the antibody response to the virus remain unanswered. Here we report that the vast majority of infected individuals with mild-to-moderate COVID-19 experience robust IgG antibody responses against the viral spike protein, based on a dataset of 30,082 individuals screened at Mount Sinai Health System in New York City. We also show that titers are relatively stable for at least a period approximating 5 months and that anti-spike binding titers significantly correlate with neutralization of authentic SARS-CoV-2. Our data suggests that more than 90% of seroconverters make detectible neutralizing antibody responses. These titers remain relatively stable for several months after infection.

bioRxiv, 14 October 2020 [preprint] - Obesity alters Ace2 and Tmprss2 expression in lung, trachea, and esophagus in a sex-dependent manner: Implications for COVID-19

Title:

Obesity alters Ace2 and Tmprss2 expression in lung, trachea, and esophagus in a sex-dependent manner: Implications for COVID-19

 

Authors:

Dylan C Sarver & G William Wong

 

Published:

bioRxiv, 14 October 2020

[Keep in mind that this article is a preprint and not yet peer reviewed.]

https://www.biorxiv.org/content/10.1101/2020.10.13.337907v1

 

Abstract:

Obesity is a major risk factor for SARS-CoV-2 infection and COVID-19 severity. The underlying basis of this association is likely complex in nature. The host-cell receptor angiotensin converting enzyme 2 (ACE2) and the type II transmembrane serine protease (TMPRSS2) are important for viral cell entry. It is unclear whether obesity alters expression of Ace2 and Tmprss2 in the lower respiratory tract. Here, we show that: 1) Ace2 expression is elevated in the lung and trachea of diet-induced obese male mice and reduced in the esophagus of obese female mice relative to lean controls; 2) Tmprss2 expression is increased in the trachea of obese male mice but reduced in the lung and elevated in the trachea of obese female mice relative to lean controls; 3) in chow-fed lean mice, females have higher expression of Ace2 in the lung and esophagus as well as higher Tmprss2 expression in the lung but lower expression in the trachea compared to males; and 4) in diet-induced obese mice, males have higher expression of Ace2 in the trachea and higher expression of Tmprss2 in the lung compared to females, whereas females have higher expression of Tmprss2 in the trachea relative to males. Our data indicate diet- and sex-dependent modulation of Ace2 and Tmprss2 expression in the lower respiratory tract and esophagus. Given the high prevalence of obesity worldwide and a sex-biased mortality rate, we discuss the implications and relevance of our results for COVID-19.

bioRxiv, 21 September 2020 (preprint) - Baseline T cell immune phenotypes predict virologic and disease control upon SARS-CoV infection

Title:

Baseline T cell immune phenotypes predict virologic and disease control upon SARS-CoV infection

 

Authors:

Jessica Graham, Jessica Swarts, Sarah R Leist, Alexandra Schafer, Vineet D Menachery, Lisa Gralinski, Sophia Jeng, Darla R Miller, Michael Mooney, Shannon McWeeney, Martin T. Ferris, Fernando Pardo-Manuel de Villena, Mark T. Heise, Ralph S. Baric & Jennifer M Lund

 

Published:

bioRxiv, 21 September 2020

[Keep in mind that this article is a preprint and not yet  reviewed.]

https://www.biorxiv.org/content/10.1101/2020.09.21.306837v1

 

Abstract:

The COVID-19 pandemic has revealed that infection with SARS-CoV-2 can result in a wide range of clinical outcomes in humans, from asymptomatic or mild disease to severe disease that can require mechanical ventilation. An incomplete understanding of immune correlates of protection represents a major barrier to the design of vaccines and therapeutic approaches to prevent infection or limit disease. This deficit is largely due to the lack of prospectively collected, pre-infection samples from indiviuals that go on to become infected with SARS-CoV-2. Here, we utilized data from a screen of genetically diverse mice from the Collaborative Cross (CC) infected with SARS-CoV to determine whether circulating baseline T cell signatures are associated with a lack of viral control and severe disease upon infection. SARS-CoV infection of CC mice results in a variety of viral load trajectories and disease outcomes. Further, early control of virus in the lung correlates with an increased abundance of activated CD4 and CD8 T cells and regulatory T cells prior to infections across strains. A basal propensity of T cells to express IFNg and IL17 over TNFa also correlated with early viral control. Overall, a dysregulated, pro-inflammatory signature of circulating T cells at baseline was associated with severe disease upon infection. While future studies of human samples prior to infection with SARS-CoV-2 are required, our studies in mice with SARS-CoV serve as proof of concept that circulating T cell signatures at baseline can predict clinical and virologic outcomes upon SARS-CoV infection. Identification of basal immune predictors in humans could allow for identification of individuals at highest risk of severe clinical and virologic outcomes upon infection, who may thus most benefit from available clinical interventions to restrict infection and disease.

 

medRxiv, 31 August 2020 [preprint] - The Role of Air Conditioning in the Diffusion of Sars-CoV-2 in Indoor Environments: a First Computational Fluid Dynamic Model, based on Investigations performed at the Vatican State Childrens Hospital

Title:
The Role of Air Conditioning in the Diffusion of Sars-CoV-2 in Indoor Environments: a First Computational Fluid Dynamic Model, based on Investigations performed at the Vatican State Childrens Hospital

Authors:
Luca Borro, Lorenzo Mazzei, Massimiliano Raponi, Prisco Piscitelli, Alessandro Miani & Aurelio Secinaro

Published:
medRxiv, 31 August 2020
[Keep in mind that this article is a preprint and not yet peer reviewed.]
https://www.medrxiv.org/content/10.1101/2020.08.25.20181420v1

From the abstract:
Background: About 15 million people worldwide were affected by the Sars-Cov-2 infection, which already caused 600,000 deaths. This virus is mainly transmitted through exhalations from the airways of infected persons, so that Heating, Ventilation and Air Conditioning (HVAC) systems might play a role in spreading the infection in indoor environments.

Coronavirus research updates: Severely ill people yield diverse trove of powerful antibodies. Nature wades through the literature on the new coronavirus - and summarizes key papers as they appear

Title:
Coronavirus research updates: Severely ill people yield diverse trove of powerful antibodies. Nature wades through the literature on the new coronavirus - and summarizes key papers as they appear.

Published:
Nature, 22 July 2020
https://www.nature.com/articles/d41586-020-00502-w

From the article:
Scientists have identified a diverse group of antibodies that block the new coronavirus’s ability to infect cells — even when applied in low doses.

medRxiv, 11 July 2020 (preprint) - Longitudinal evaluation and decline of antibody responses in SARS-CoV-2 infection

Title:
Longitudinal evaluation and decline of antibody responses in SARS-CoV-2 infection

Authors:
Jeffrey Seow, Carl Graham, Blair Merrick, Sam Acors, Kathryn J.A. Steel, Oliver Hemmings, Aoife O'Bryne, Neophytos Kouphou, Suzanne Pickering, Rui Galao, Gilberto Betancor, Harry D Wilson, Adrian W Signell, Helena Winstone, Claire Kerridge, Nigel Temperton, Luke Snell, Karen Bisnauthsing, Amelia Moore, Adrian Green, Lauren Martinez, Brielle Stokes, Johanna Honey, Alba Izquierdo-Barras, Gill Arbane, Amita Patel, Lorcan OConnell, Geraldine O Hara, Eithne MacMahon, Sam Douthwaite, Gaia Nebbia, Rahul Batra, Rocio Martinez-Nunez, Jonathan D. Edgeworth, Stuart J.D. Neil, Michael H. Malim & Katie Doores

Published:
medRxiv, 11 July 2020
[Keep in mind that this article is a preprint and not yet peer reviewed.]
https://www.medrxiv.org/content/10.1101/2020.07.09.20148429v1

Abstract:
Antibody (Ab) responses to SARS-CoV-2 can be detected in most infected individuals 10-15 days following the onset of COVID-19 symptoms. However, due to the recent emergence of this virus in the human population it is not yet known how long these Ab responses will be maintained or whether they will provide protection from re-infection. Using sequential serum samples collected up to 94 days post onset of symptoms (POS) from 65 RT-qPCR confirmed SARS-CoV-2-infected individuals, we show seroconversion in >95% of cases and neutralizing antibody (nAb) responses when sampled beyond 8 days POS. We demonstrate that the magnitude of the nAb response is dependent upon the disease severity, but this does not affect the kinetics of the nAb response. Declining nAb titres were observed during the follow up period. Whilst some individuals with high peak ID50 (>10,000) maintained titres >1,000 at >60 days POS, some with lower peak ID50 had titres approaching baseline within the follow up period. A similar decline in nAb titres was also observed in a cohort of seropositive healthcare workers from Guy′s and St Thomas′ Hospitals. We suggest that this transient nAb response is a feature shared by both a SARS-CoV-2 infection that causes low disease severity and the circulating seasonal coronaviruses that are associated with common colds. This study has important implications when considering widespread serological testing, Ab protection against re-infection with SARS-CoV-2 and the durability of vaccine protection.

Tuscaloosa, Alabama, United States of America - US university students are reportedly throwing 'Covid parties', gambling on who gets sick first

Title:
US university students are reportedly throwing 'Covid parties', gambling on who gets sick first

Author:
Ashley Collman

Published:
Business Insider, 4 July 2020
https://www.businessinsider.co.za/trending/alabama-students-covid-parties-bet-on-who-gets-sick-2020-7

From the article:
* College students in Tuscaloosa, Alabama, have been throwing parties in which they invite people infected with the coronavirus and gamble on who comes down with the illness first, city officials say.
* As of Thursday, the state had confirmed more than 38,000 coronavirus cases and 947 deaths. Authorities have warned that intensive-care-unit beds might run out.

Scholarly Article (Science, 2 July 2020) - Primary exposure to SARS-CoV-2 protects against reinfection in rhesus macaques

Title:
Primary exposure to SARS-CoV-2 protects against reinfection in rhesus macaques

Author:
Wei Deng, Linlin Bao, Jiangning Liu, Chong Xiao, Jiayi Liu, Jing Xue, Qi Lv, Feifei Qi, Hong Gao, Pin Yu, Yanfeng Xu, Yajin Qu, Fengdi Li, Zhiguang Xiang, Haisheng Yu, Shuran Gong, Mingya Liu, Guanpeng Wang, Shunyi Wang, Zhiqi Song, Ying Liu, Wenjie Zhao, Yunlin Han, Linna Zhao, Xing Liu, Qiang Wei & Chuan Qin

Published:
Science, 2 July 2020
https://science.sciencemag.org/content/early/2020/07/01/science.abc5343.full

Abstract:
Coronavirus disease 2019 (COVID-19), which is caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic. It currently remains unclear whether convalescing patients have a risk of reinfection. We generated a rhesus macaque model of SARS-CoV-2 infection that was characterized by interstitial pneumonia and systemic viral dissemination mainly in the respiratory and gastrointestinal tracts. Rhesus macaques reinfected with the identical SARS-CoV-2 strain during the early recovery phase of the initial SARS-CoV-2 infection did not show detectable viral dissemination, clinical manifestations of viral disease, or histopathological changes. Comparing the humoral and cellular immunity between primary infection and rechallenge revealed notably enhanced neutralizing antibody and immune responses. Our results suggest that primary SARS-CoV-2 exposure protects against subsequent reinfection in rhesus macaques.

Centers for Disease Control and Prevention (CDC), updated 30 June 2020 - Test for Past Infection (Antibody Test) - What do your results mean? If you test positive / If you test negative

Test for Past Infection (Antibody Test)
- What do your results mean? If you test positive / If you test negative
 
Published by:
Centers for Disease Control and Prevention (CDC), updated 30 June 2020
https://www.cdc.gov/coronavirus/2019-ncov/testing/serology-overview.html
 
From the article:
 
What do your results mean? If you test positive
* A positive test result shows you may have antibodies from an infection with the virus that causes COVID-19. However, there is a chance a positive result means that you have antibodies from an infection with a virus from the same family of viruses (called coronaviruses), such as the one that causes the common cold.
* Having antibodies to the virus that causes COVID-19 may provide protection from getting infected with the virus again. If it does, we do not know how much protection the antibodies may provide or how long this protection may last.
* Talk with your healthcare provider about your test result and the type of test you took to understand what your result means. Your provider may suggest you take a second type of antibody test to see if the first test was accurate.
* You should continue to protect yourself and others since you could get infected with the virus again.
   > If you work in a job where you wear personal protective equipment (PPE), continue wearing PPE.
* You may test positive for antibodies even if you have never had symptoms of COVID-19. This can happen if you had an infection without symptoms, which is called an asymptomatic infection.
 
What do your results mean? If you test negative
* You may not have ever had COVID-19. Talk with your healthcare provider about your test result and the type of test you took to understand what your result means.
* You could still have a current infection.
   > The test may be negative because it typically takes 1–3 weeks after infection for your body to make antibodies. It’s possible you could still get sick if you have been exposed to the virus recently. This means you could still spread the virus.
   > Some people may take even longer to develop antibodies, and some people who are infected may not ever develop antibodies.
* If you get symptoms after the antibody test, you might need another test called a viral test​.
 
Regardless of whether you test positive or negative, the results do not confirm whether or not you are able to spread the virus that causes COVID-19. Until we know more, continue to take steps to protect yourself and others.

Here are the deaths by age in South Africa’s coronavirus hotspots - The latest data from the Department of Health shows a clear correlation between age and the coronavirus mortality rate

Title:
Here are the deaths by age in South Africa’s coronavirus hotspots

Published:
BusinessTech, 25 June 2020
https://businesstech.co.za/news/trending/410895/here-are-the-deaths-by-age-in-south-africas-coronavirus-hotpsots/

From the article:
As of 24 June, the country has a total of 2,205 deaths – a mortality rate of 2%. The majority of these deaths were reported in the 50+ age group.

medRxiv, 26 May 2020 - Estimating Household Transmission of SARS-CoV-2

Title:
Estimating Household Transmission of SARS-CoV-2

Authors:
Mihaela Curmei, Andrew Ilyas, Owain Evans & Jacob Steinhardt

Published:
medRxiv, 26 May 2020
https://www.medrxiv.org/content/10.1101/2020.05.23.20111559v1
[Keep in mind that this article is not yet peer-reviewed.]

From the abstract:
Introduction and Goals: 
"SARS-CoV-2 is transmitted both in the community and within households. Social distancing and lockdowns reduce community transmission but do not directly address household transmission. We provide quantitative measures of household transmission based on empirical data, and estimate the contribution of households to overall spread. We highlight policy implications from our analysis of household transmission, and more generally, of changes in contact patterns under social distancing."

Star Rapid video (7 May 2020) - How To Prevent Your Company From COVID-19 Infections? - 6 Steps To Prevent Coronavirus Infections

Title of video (9:16):
How To Prevent Your Company From COVID-19 Infections? - 6 Steps To Prevent Coronavirus Infections

Published:
Star Rapid, 7 May 2020
https://www.youtube.com/watch?v=xpn7LoHEg94

Note:
"If you are going back to work, then you MUST watch this. Six important steps to prevent you and your company from #covid19 infections."

medRxiv, 19 May 2020 - The infection fatality rate of COVID-19 inferred from seroprevalence data [& blog posts relating to this article] - fascinating

Title:
The infection fatality rate of COVID-19 inferred from seroprevalence data

Author:
John Ioannidis, Stanford University

Published:
medRxiv, 19 May 2020
[Keep in mind that this study has not been peer-reviewed.]
https://www.medrxiv.org/content/10.1101/2020.05.13.20101253v1

From the abstract:
1) Objective: 
To estimate the infection fatality rate of coronavirus disease 2019 (COVID-19) from data of seroprevalence studies. 

2) Methods:
Population studies with sample size of at least 500 and published as peer-reviewed papers or preprints as of May 12, 2020 were retrieved from PubMed, preprint servers, and communications with experts. Studies on blood donors were included, but studies on healthcare workers were excluded. The studies were assessed for design features and seroprevalence estimates. Infection fatality rate was estimated from each study dividing the number of COVID-19 deaths at a relevant time point by the number of estimated people infected in each relevant region. Correction was also attempted accounting for the types of antibodies assessed.

3) Results:
Twelve studies were identified with usable data to enter into calculations. Seroprevalence estimates ranged from 0.113% to 25.9% and adjusted seroprevalence estimates ranged from 0.309% to 33%. Infection fatality rates ranged from 0.03% to 0.50% and corrected values ranged from 0.02% to 0.40%.

4) Conclusions:
The infection fatality rate of COVID-19 can vary substantially across different locations and this may reflect differences in population age structure and case-mix of infected and deceased patients as well as multiple other factors. Estimates of infection fatality rates inferred from seroprevalence studies tend to be much lower than original speculations made in the early days of the pandemic. 


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