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Asymptomatic SARS-CoV-2 infections responsible for spreading of COVID-19 less than symptomatic infections

Based on studies published through July 2021, most SARS-CoV-2 infections were not persistently asymptomatic, and asymptomatic infections were less infectious…

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Based on studies published through July 2021, most SARS-CoV-2 infections were not persistently asymptomatic, and asymptomatic infections were less infectious than symptomatic infections. These are the conclusions of an update of a systematic review and meta-analysis publishing May 26th in the open access journal PLOS Medicine by Diana Buitrago-Garcia of the University of Bern, Switzerland, and colleagues.

Credit: Monstera, Pexels (CC0, https://creativecommons.org/publicdomain/zero/1.0/)

Based on studies published through July 2021, most SARS-CoV-2 infections were not persistently asymptomatic, and asymptomatic infections were less infectious than symptomatic infections. These are the conclusions of an update of a systematic review and meta-analysis publishing May 26th in the open access journal PLOS Medicine by Diana Buitrago-Garcia of the University of Bern, Switzerland, and colleagues.

Debate about the level and risks of asymptomatic SARS-CoV-2 infections continues, with much ongoing research. Studies that assess people at just one time point can overestimate the proportion of true asymptomatic infections because those who go on to later develop symptoms are incorrectly classified as asymptomatic rather than presymptomatic. However, other studies can underestimate asymptomatic infections with research designs that are more likely to include symptomatic participants.

The new paper was an update of a living (as in, regularly updated) systematic review first published in April 2020, which includes additional, more recent studies through July 2021. 130 studies were included, with data on 28,426 people with SARS-CoV-2 across 42 countries, including 11,923 people defined as having asymptomatic infection. Because of extreme variability between included studies, the meta-analysis did not calculate a single estimate for asymptomatic infection rate, but it did estimate the inter-quartile range to be that 14–50% of infections were asymptomatic. Additionally, the researchers found that the secondary attack rate—a measure of the risk of transmission of SARS-CoV-2 — was about two-thirds lower from people without symptoms than from those with symptoms (risk ratio 0.32, 95%CI 0.16–0.64).

“If both the proportion and transmissibility of asymptomatic infection are relatively low, people with asymptomatic SARS-CoV-2 infection should account for a smaller proportion of overall transmission than presymptomatic individuals,” the authors say, while also pointing out that “when SARS-CoV-2 community transmission levels are high, physical distancing measures and mask-wearing need to be sustained to prevent transmission from close contact with people with asymptomatic and presymptomatic infection.”

Coauthor Nicola Low adds, “The true proportion of asymptomatic SARS-CoV-2 infection is still not known, and it would be misleading to rely on a single number because the 130 studies that we reviewed were so different. People with truly asymptomatic infection are, however, less infectious than those with symptomatic infection.”

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In your coverage, please use this URL to provide access to the freely available paper in PLOS Medicine:

http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003987  

Citation: Buitrago-Garcia D, Ipekci AM, Heron L, Imeri H, Araujo-Chaveron L, Arevalo-Rodriguez I, et al. (2022) Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: Update of a living systematic review and meta-analysis. PLoS Med 19(5): e1003987. https://doi.org/10.1371/journal.pmed.1003987

Author Countries: Switzerland, France, Spain, Argentina, United Kingdom, Sweden, United States, Colombia

Funding: This study was funded by the Swiss National Science Foundation http://www.snf.ch/en (NL: 320030_176233); the European Union Horizon 2020 research and innovation programme https://ec.europa.eu/programmes/horizon2020/en (NL: 101003688); the Swiss government excellence scholarship https://www.sbfi.admin.ch/sbfi/en/home/education/scholarships-and-grants/swiss-government-excellence-scholarships.html (DBG: 2019.0774) and the Swiss School of Public Health Global P3HS stipend https://ssphplus.ch/en/ (DBG). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.


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Government

New Hampshire Governor Vetoes Ivermectin Bill

New Hampshire Governor Vetoes Ivermectin Bill

Authored by Alice Giordano via The Epoch Times (emphasis ours),

New Hampshire’s Republican…

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New Hampshire Governor Vetoes Ivermectin Bill

Authored by Alice Giordano via The Epoch Times (emphasis ours),

New Hampshire’s Republican Gov. Chris Sununu vetoed a bill that would have made Ivermectin available without a prescription.

Ivermectin tablets packaged for human use. (Natasha Holt/The Epoch Times)

The Republican governor vetoed the bill on June 24, the same day that the U.S. Supreme Court overturned Roe v. Wade. Some fellow Republicans questioned the timing.

It certainly seemed like a convenient way to bury a veto of a bill that won support from the vast majority of Republicans in New Hampshire,” JR Hoell, co-founder of the conservative watchdog group RebuildNH, told The Epoch Times.

Hoell is a former four-term House Republican planning to seek re-election after a four-year hiatus from the the New Hampshire legislature.

Earlier this year, the New Hampshire Department of Children Youth and Family (DCYF) tried to take custody of Hoell’s 13-year old son after a nurse reported him for giving human-grade ivermectin to the teen months earlier.

Several states have introduced bills to make human-grade ivermectin available without a prescription at a brick and mortar store. Currently, it can be ordered online from another country. In April, Tennessee became the the first state to sign such a measure into law. New Hampshire lawmakers were first to introduce the idea.

Both chambers of the state’s Republican controlled legislature approved the bill.

In his statement explaining the veto, Sununu noted that there are only four other controlled medications available without a prescription in New Hampshire and that each were only made available after “rigorous reviews and vetting to ensure” before being dispensed.

“Patients should always consult their doctor before taking medications so that they are fully aware of treatment options and potential unintended consequences of taking a medication that may limit other treatment options in the future,” Sununu said in his statement.

Sununu’s statement is very similar to testimony given by Paula Minnehan, senior vice president of state government regulations for the New Hampshire Hospital Association, at hearings on the bill.

Minnehan too placed emphasis on the review that went into the four prescription medications the state made available under a standing order. They include naloxone, the generic name for Narcan, which is used to counter opioid overdoses, hormone replacement therapy drugs, and a prescription-version of the morning after pill.

It also includes a collection of smoking cessation therapy drugs like Chantix, which has been linked to suicide, depression, and other neuropsychiatric conditions. Last year, Pfizer, the leading maker of the FDA-approved drug, conducted a voluntarily recall of Chantix. Narcan has also been linked to deaths caused by severe withdrawals that have led to acute respiratory distress.

Rep. Melissa Blasek, a Republican co-sponsor of the New Hampshire ivermectin bill, told The Epoch Times, that one could veto any drug-related bill under the pretense of overdose concerns.

The reality is you can overdose on Tylenol,” she said. “Ivermectin has one of the safest track records of any drug.”

The use of human-grade ivermectin became controversial when some doctors began promoting it for the treatment and prevention of COVID-19. Government agencies including the FDA and CDC issued warnings against its use while groups like Front Line COVID-19 Critical Care Alliance (FLCCC) heavily promoted it.

Some doctors were  disciplined for prescribing human-grade ivermectin for COVID-19 including a Maine doctor whose medical license was suspended by the state.

Read more here...

Tyler Durden Thu, 06/30/2022 - 20:30

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Aging-US | Time makes histone H3 modifications drift in mouse liver

BUFFALO, NY- June 30, 2022 – A new research paper was published in Aging (Aging-US) on the cover of Volume 14, Issue 12, entitled, “Time makes histone…

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BUFFALO, NY- June 30, 2022 – A new research paper was published in Aging (Aging-US) on the cover of Volume 14, Issue 12, entitled, “Time makes histone H3 modifications drift in mouse liver.”

Credit: Hillje et al.

BUFFALO, NY- June 30, 2022 – A new research paper was published in Aging (Aging-US) on the cover of Volume 14, Issue 12, entitled, “Time makes histone H3 modifications drift in mouse liver.”

Aging is known to involve epigenetic histone modifications, which are associated with transcriptional changes, occurring throughout the entire lifespan of an individual.

“So far, no study discloses any drift of histone marks in mammals which is time-dependent or influenced by pro-longevity caloric restriction treatment.”

To detect the epigenetic drift of time passing, researchers—from Istituto di Ricovero e Cura a Carattere Scientifico, University of Urbino ‘Carlo Bo’, University of Milan, and University of Padua—determined the genome-wide distributions of mono- and tri-methylated lysine 4 and acetylated and tri-methylated lysine 27 of histone H3 in the livers of healthy 3, 6 and 12 months old C57BL/6 mice. 

“In this study, we used chromatin immunoprecipitation sequencing technology to acquire 108 high-resolution profiles of H3K4me3, H3K4me1, H3K27me3 and H3K27ac from the livers of mice aged between 3 months and 12 months and fed 30% caloric restriction diet (CR) or standard diet (SD).”

The comparison of different age profiles of histone H3 marks revealed global redistribution of histone H3 modifications with time, in particular in intergenic regions and near transcription start sites, as well as altered correlation between the profiles of different histone modifications. Moreover, feeding mice with caloric restriction diet, a treatment known to retard aging, reduced the extent of changes occurring during the first year of life in these genomic regions.

“In conclusion, while our data do not establish that the observed changes in H3 modification are causally involved in aging, they indicate age, buffered by caloric restriction, releases the histone H3 marking process of transcriptional suppression in gene desert regions of mouse liver genome most of which remain to be functionally understood.”

DOI: https://doi.org/10.18632/aging.204107 

Corresponding Author: Marco Giorgio – marco.giorgio@unipd.it 

Keywords: epigenetics, aging, histones, ChIP-seq, diet

Sign up for free Altmetric alerts about this article:  https://aging.altmetric.com/details/email_updates?id=10.18632%2Faging.204107

About Aging-US:

Launched in 2009, Aging (Aging-US) publishes papers of general interest and biological significance in all fields of aging research and age-related diseases, including cancer—and now, with a special focus on COVID-19 vulnerability as an age-dependent syndrome. Topics in Aging go beyond traditional gerontology, including, but not limited to, cellular and molecular biology, human age-related diseases, pathology in model organisms, signal transduction pathways (e.g., p53, sirtuins, and PI-3K/AKT/mTOR, among others), and approaches to modulating these signaling pathways.

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Government

FDA asks for COVID boosters to fight Omicron’s BA.4, BA.5 subvariants

The U.S. Food and Drug Administration on Thursday recommended booster doses of COVID-19 vaccines be modified beginning this fall to include components…

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FDA asks for COVID boosters to fight Omicron’s BA.4, BA.5 subvariants

By Michael Erman

June 30 (Reuters) – The U.S. Food and Drug Administration on Thursday recommended booster doses of COVID-19 vaccines be modified beginning this fall to include components tailored to combat the currently dominant Omicron BA.4 and BA.5 subvariants of the coronavirus.

The FDA said manufacturers would not need to change the vaccine for the primary vaccination series, saying the coming year will be “a transitional period when this modified booster vaccine may be introduced.”

FILE PHOTO: Signage is seen outside of the Food and Drug Administration (FDA) headquarters in White Oak, Maryland, U.S., August 29, 2020. REUTERS/Andrew Kelly/File Photo

The new booster shots would be bivalent vaccines, meaning doses would target both the original virus as well as the Omicron subvariants.

The decision follows a recommendation by the agency’s outside advisers to change the design of the shots this fall in order to combat more prevalent versions of the coronavirus. read more

BA.4 and BA.5 are now estimated to account for more than 50% of U.S. infections, according the U.S. Centers for Disease Control and Prevention, and have also become dominant elsewhere.

The FDA said in a statement on Thursday that it hoped the modified vaccines could be used in early to mid-fall.

Pfizer Inc (PFE.N) with partner BioNTech SE (22UAy.DE) and Moderna Inc (MRNA.O) have been testing versions of their vaccines modified to combat the BA.1 Omicron variant that caused the massive surge in cases last winter.

Although they have said those vaccines worked against BA.1 and the more recently circulating variants, they did see a lower immune response against BA.4 and BA.5.

The companies had already been manufacturing their BA.1 vaccines, and said on Tuesday that swapping to a BA.4/BA.5 version could slow the rollout.

Pfizer/BioNTech, which on Wednesday announced a $3.2 billion contract to supply more COVID vaccine doses to the United States, said they would have a substantial amount of BA.4/BA.5 vaccine ready for distribution by the first week of October. read more

Moderna said it would be late October or early November before it would have the newly modified vaccine ready.

Reporting by Michael Erman in New Jersey and Leroy Leo in Bengaluru; Editing by Jonathan Oatis and Bill Berkrot

Our Standards: The Thomson Reuters Trust Principles.

Source: Reuters

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