Epidemiology & Impact (Deaths, Hospitals, Cancer, Alzheimer's etc)

Background Pre-Delta, vaccination reduced SARS-CoV-2 transmission from individuals infected despite vaccination, potentially via reducing viral loads. While vaccination still lowers the risk of infection, similar viral loads in vaccinated and unvaccinated individuals infected with Delta question how much vaccination prevents transmission. Methods We performed a retrospective observational cohort study of adult contacts of SARS-CoV-2-infected adult index cases using English contact testing data. We used multivariable Poisson regression to investigate associations between transmission and index case and contact vaccination, and how these vary with Alpha and Delta variants (classified using S-gene detection/calendar trends) and time since second vaccination. Results 54,667/146,243(37.4%) PCR-tested contacts of 108,498 index cases were PCR-positive. Two doses of BNT162b2 or ChAdOx1 vaccines in Alpha index cases were independently associated with reduced PCR-positivity in contacts (aRR, adjusted rate ratio vs. unvaccinated=0.32[95%CI 0.21-0.48] and 0.48[0.30-0.78] respectively). The Delta variant attenuated vaccine-associated reductions in transmission: two BNT162b2 doses reduced Delta transmission (aRR=0.50[0.39-0.65]), more than ChAdOx1 (aRR=0.76[0.70-0.82]). Variation in Ct values (indicative of viral load) explained 7-23% of vaccine-associated transmission reductions. Transmission reductions declined over time post-second vaccination, for Delta reaching similar levels to unvaccinated individuals by 12 weeks for ChAdOx1 and attenuating substantially for BNT162b2. Protection in contacts also declined in the 3 months post-second vaccination. Conclusions Vaccination reduces transmission of Delta, but by less than the Alpha variant. The impact of vaccination decreased over time. Factors other than PCR Ct values at diagnosis are important in understanding vaccine-associated transmission reductions. Booster vaccinations may help control transmission together with preventing infections. ### Competing Interest Statement DWE declares lecture fees from Gilead outside the submitted work. No other author has a conflict of interest to declare. ### Funding Statement This study was funded by the UK Government's Department of Health and Social Care. This work was supported by the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Healthcare Associated Infections and Antimicrobial Resistance at Oxford University in partnership with Public Health England (PHE) (NIHR200915), and the NIHR Biomedical Research Centre, Oxford. The views expressed in this publication are those of the authors and not necessarily those of the NHS, the National Institute for Health Research, the Department of Health or Public Health England. DWE is a Robertson Foundation Fellow and an NIHR Oxford BRC Senior Fellow. ASW is an NIHR Senior Investigator. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was performed as public health surveillance and NHS Test and Trace program quality assurance, under Section 251 of the NHS Act 2006 with approvals from Public Health England (PHE), the Department of Health and Social Care and NHS Test and Trace. PHE's Research Ethics and Governance Group (PHE's Research Ethics Committee) reviewed the study protocol and confirmed compliance with all regulatory requirements. As no regulatory or ethical issues were identified, it was agreed that full ethical review was not needed, and the protocol was approved. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Applications to use the data in this study can be made to NHS Digital's Data Access Request Service, please see for more details.

Both the Canadian and Ontario medical associations believe that intentional bullying directed at physicians and health-care workers is a crime and should be actively prosecuted.

Breakthrough COVID-19 cases in vaccinated people may be less likely to spread infection because virus is shed for a shorter period of time as opposed to infections in unvaccinated people.

A lack of testing data and government guidance led many to avoid the COVID-19 vaccine during pregnancy, unwittingly increasing their chances of a stillbirth.

Montana’s GOP-led COVID response brought waves of patients to a Helena hospital, forcing health care workers to make difficult care decisions for COVID and non-COVID patients alike.

Professor Massimo Hilliard and Dr Ramon Martinez-Marmol have discovered viruses such as SARS-CoV-2 can cause brain cells to fuse, initiating malfunctions that lead to chronic neurological symptoms.

The World Health Organization has walked back a top official’s claim that asymptomatic people rarely spread the coronavirus to others. The WHO’s confused messaging on the topic drew criticism from public health officials. The Harvard Global Health Institute said, “In fact, some evidence suggests that people may be most infectious in the days before they become symptomatic — that is, in the presymptomatic phase when they feel well, have no symptoms, but may be shedding substantial amounts of virus.” Meanwhile, two new papers published in the journal Nature find coronavirus lockdowns saved millions of lives and averted tens of millions of infections worldwide. UC Berkeley researcher Solomon Hsiang co-authored one of the reports. Solomon Hsiang: “Never in human history have so many people around the world come together, coordinated their actions and worked to save so many lives in such a short period of time.”

Millions of people worldwide are getting infected or re-infected with highly transmissible Omicron subvariants. And yet millions of people in low and middle-income nations are still lacking access to vaccines and tools. World leaders have failed to unite against the virus.

A manifesto urging reliance on “herd immunity” without lockdowns was warmly received by administration officials. But the strategy cannot stem the pandemic, many experts say.

January 7, 2021 Introduction: In recent months, there has been a great deal of discussion about herd immunity.  This became a hot topic during the COVID-19 pandemic, particularly the notion of…

Measles once killed millions every year. Vaccines changed this, preventing disease, long-term immune damage, and deadly outbreaks.

In St. Thomas, Ontario, Asmaa Hussain is on the frontlines treating unvaccinated patients. As vaccine refusal grows in Canada, she wonders if other preventable diseases are next.

Purpose Although COVID-19 typically presents with respiratory symptoms, it can also lead to severe neurological manifestations in children. While case reports of COVID-19–associated encephalopathy (including acute necrotizing encephalopathy) have increasingly appeared, gaps remain regarding optimal management strategies and outcome predictors for children with rapid-onset neurological decline. This report aims to underscore the critical need for standardized clinical approaches to severe pediatric COVID-19–related encephalopathy. Methods In this case report, We detail the case of an 8-year-old girl who presented with fever, rash, headache, and recurrent seizures. Her diagnostic workup included polymerase chain reaction (PCR) testing for SARS-CoV-2 and a range of neurological assessments: contrast-enhanced computed tomography (CT) to evaluate structural changes, transcranial Doppler ultrasound to assess intracranial hemodynamics, and electroencephalography (EEG) to monitor electrical activity. Intensive therapeutic measures—encompassing mechanical ventilation, hemodynamic support, antimicrobial agents, and corticosteroids—were initiated. In addition, a targeted narrative literature review of pediatric COVID-19–associated neurological complications was conducted to contextualize this presentation. Results The patient tested positive for COVID-19;imaging revealed brain edem, and EEG suggested brain death. Despite aggressive critical care interventions, her condition did not improve, ultimately resulting in brain death. Our review of current literature revealed several reported instances of acute necrotizing encephalopathy in pediatric COVID-19, highlighting a growing body of evidence on the potential for severe central nervous system sequelae. Conclusion This case highlights the importance of early recognition and close neurological surveillance in pediatric patients with COVID-19. Although accumulating evidence describes COVID-19–related neurological complications such as acute necrotizing encephalopathy, uncertainties persist regarding definitive treatment protocols and long-term outcomes. Greater understanding of the underlying mechanisms and standardized management pathways is imperative to improve prognosis in this vulnerable population. Clinical trial Not applicable.

Pediatric long COVID is more common than many thought, and we keep letting kids be reinfected with new variants

Public health authorities say the Covid-19 vaccines have saved lives, but a Canadian report shared across platforms estimates the shots have killed 17 million people globally. This is false; government agencies and independent experts worldwide told AFP the findings are flawed and that only a minuscule percentage of deaths among the vaccinated can be attributed to the jabs.

Here we go again – bad published research tries to convince us that COVID-19 rates are unrelated to the uptake of COVID-19 vaccines in several countries

The COVID-19 Monitor measures the ongoing impact and implications of the novel coronavirus pandemic. It includes unique indicators that offer robust insights into societal health and well-being.

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Of the 400 cases, 398 were people who were unvaccinated or had an unknown vaccination status.

Explore this post and more from the Coronavirus community

A critical look at the Great Barrington Declaration, exposing the risks of herd immunity strategies and the spread of harmful COVID-19 misinformation.

Five years later, the greatest basic science failure in generations caused the pandemic harms highlighted by people across the political spectrum, and broke our social cohesion.

An unvaccinated child has died of measles, Texas officials announced Wednesday, the first death from measles in the United States in a decade. The child’s death in a hospital in Lubbock, in West Texas, comes as the largest measles outbreak in the state in over 30 years is now spreading to New Mexico. Since last month, 124 people have contracted the disease, most of them unvaccinated children. “The minute you stop vaccinating and maintaining that vigilance of 90-95% vaccine coverage, measles comes roaring back, and that’s what’s happened here in West Texas,” world-renowned pediatrician, virologist and vaccine expert, Dr. Peter Hotez, tells Democracy Now!

7.3K votes, 234 comments. 34M subscribers in the science community. This community is a place to share and discuss new scientific research. Read…

Q: How do people who have not been vaccinated against COVID-19 pose a risk to people who have been vaccinated? A: An unvaccinated person who is infected with COVID-19 poses a much greater risk to others who are also unvaccinated. But vaccines are not 100% effective, so there is a chance that an unvaccinated person could infect a vaccinated person — particularly the vulnerable, such as elderly and immunocompromised individuals.

387 votes, 43 comments. 234K subscribers in the skeptic community. A sub for "scientific skepticism." Scientific Skepticism is about combining…

Some 10 to 30% of Americans who’ve been infected with SARS-CoV-2 are still having debilitating symptoms months later, a trend that suggests that “long Covid” is our next public health disaster in t...

New research has found inflammatory markers in the blood of long COVID patients which could explain why many experience ongoing cardiovascular issues.