Coronavirus Tidbits #250, June 18, 2023

What makes a COVID superspreader? Scientists learn more after deliberately infecting volunteers

Nature Saima Sidik  15 June 2023

A study of people who were intentionally infected with SARS-CoV-2 has provided a wealth of insights into viral transmission — showing, for example, that a select group of people are ‘supershedders’ who spew vastly more virus into the air than do others¹.

The publication describes data from a controversial ‘challenge study’, in which scientists deliberately infected volunteers with the virus that causes COVID-19². Although the approach drew opposition, the work has now yielded data on questions central to public health, such as whether the severity of symptoms correlates with how contagious people are and whether home COVID-19 tests can play a part in reducing viral spread.

The results highlight how widely and unpredictably disease severity and contagiousness vary between people. ...The study, published on 9 June in Lancet Microbe, also suggests that human physiology, not the virus, is to blame for some of the inconsistency of COVID-19.

Design with benefits

Some people argue that it’s unethical to give people an infection that can cause severe illness, but the research design comes with benefits. Challenge studies can substantially speed up vaccine testing, and they’re the only way to understand certain aspects of COVID-19, such as the stage before people test positive or develop symptoms.

Researchers inoculated 34 healthy young participants by squirting a known quantity of viral particles up their noses. Eighteen developed infections and spent at least 14 days confined to hospital rooms. Each day, researchers measured viral levels in the participants’ noses and throats, in the air, and on the participants’ hands and various surfaces in the rooms.

The symptoms and severity of naturally acquired COVID-19 might vary depending on transmission route, viral strain and how much virus a person was exposed to. But in the challenge study, “we know that that was all controlled”, says infectious-disease researcher Anika Singanayagam at Imperial College London, a co-author of the paper.

Of the 18 participants who developed infections, 2 shed 86% of the airborne virus detected over the course of the entire study — even though both had only mild symptoms. Previous research³ provided evidence for the existence of superspreaders who infect large numbers of people. But whether such people are also ‘supershedders’ who emit copious amounts of virus, or simply have many social contacts was up for debate, says disease ecologist Pablo Beldomenico at the Institute of Veterinary Sciences of the Coast in Esperanza, Argentina. This study “supports the existence of supershedders”, he says.

https://www.nature.com/articles/d41586-023-01961-7

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Bivalent COVID vaccine protects against death for at least 6 months in older adults, study suggests

The bivalent (two-strain) COVID-19 booster provides substantial protection against death among US adults aged 65 years and older, with no significant signs of waning for up to 6 months, concludes a study published today in Morbidity and Mortality Weekly.

Researchers from the Centers for Disease Control and Prevention led the study and followed up on a previous report on the durability of bivalent booster protection against death among adults aged 65 and older. The team conducted the study over three periods of the SARS-CoV-2 Omicron variant wave (BA.5 substrain, September 18 to November 5, 2022; BQ.1/BQ.1.1, November 6, 2022, to January 21, 2023; and XBB.1.5, January 22 to April 1, 2023).

https://www.cidrap.umn.edu/covid-19/bivalent-covid-vaccine-protects-against-death-least-6-months-older-adults-study-suggests

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FDA panel backs monovalent XBB switch for fall COVID vaccines

Overall, data suggest waning immunity of the current bivalent (two-strain) vaccine to circulating XBB lineage strains. Also, data suggest that including the original Wuhan strain is unlikely to enhance response to the current variants....the World Health Organization recommended a shift to either XBB.1.5 or XBB.1.16.

Questions about messaging

VRBPAC members today also raised concerns about vaccine messaging, especially to specific groups, amid changes to the vaccine.

efforts are under way to transition to uniform age cutoffs and dose number recommendations. He also said the agency continues to review the need for more frequent doses for other populations. "It's a work in progress," he said.

Though the vote on the switch to a monovalent vaccine was unanimous, the group grappled with several uncertainties, such as whether a focus on a fall vaccine sends unclear messages about SARS-CoV-2 seasonality and similarities to flu. Some members also worried that a strain selection focusing on fall would preclude more frequent updates to the vaccine if there are major changes to the virus. FDA officials noted practical considerations for vaccine production as one of the reasons for a seasonal vaccine update.

https://www.cidrap.umn.edu/covid-19/fda-panel-backs-monovalent-xbb-switch-fall-covid-vaccines

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Fungal Infections More Deadly When COVID's Involved

From 2020 to 2021, the mortality rate for in-hospital COVID-associated fungal infections was 48.5% compared with 12.3% for non-COVID-associated fungal infections (P<0.01). the highest mortality rates involved aspergillosis (57.6%), invasive candidiasis (55.4%), mucormycosis (44.7%), and unspecified mycoses (59.0%), they noted in Emerging Infectious Diseases

“COVID-19 is a substantial risk factor for certain fungal infections, particularly those caused by invasive molds, likely because of COVID-19-related immune system dysregulation and immunosuppressive therapies, such as corticosteroids or other immunomodulatory medications."

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C. auris tied to 34% death rate: CDC

In a new report, the CDC analyzed 192 hospitalizations associated with Candida auris and found an estimated crude mortality rate of 34 percent.

The death rate estimates follow reports from earlier this year that found clinical cases of the drug-resistant fungus grew 95 percent from 2020 to 2021.

For the study, published June 8, CDC researchers reviewed 192 C. auris-related hospitalizations from 2017 to 2022, including 38 bloodstream infections. Hospitalizations primarily occurred among older adults, with a median age of 68. There was a high prevalence of underlying conditions and complications for patients with bloodstream and nonbloodstream C. auris, including sepsis (64 percent), diabetes (55 percent), chronic kidney disease (44 percent) and pneumonia (43 percent).

https://www.beckershospitalreview.com/public-health/c-auris-tied-to-34-death-rate-cdc.html

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Donated kidneys from deceased COVID-19 patients are safe to transplant, according to study

Kidneys from organ donors who were diagnosed with COVID-19 are safe to transplant and don't transmit the virus to people who receive those organs, according to a new study led by researchers at Washington University School of Medicine in St. Louis.

Of the many thousands of kidneys transplanted since the start of the COVID-19 pandemic, there have been no reported infections after transplant surgery related to kidneys donated by people who died and had tested positive for the virus. Most donors died of causes other than COVID-19, but even in those who had tested positive for the virus within a week of their deaths, there was no effect on the success of the transplants.

The findings are published in the journal JAMA Network Open.

https://medicalxpress.com/news/2023-06-donated-kidneys-deceased-covid-patients.html

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Millions of patients do not have full recovery of smell or taste senses after COVID infection, study finds

about 60 percent of surveyed participants infected with COVID experienced a loss of smell and about 58 percent experienced loss of taste. Additionally, not all the patients experienced a full recovery of their senses once they recovered from their infection.

The study found that around 72 percent of patients fully recovered their sense of smell, but 24 percent only had a partial recovery and over 3 percent had no recovery of their sense of smell at all. Similarly, of those who experienced a loss of taste due to COVID, about 76 percent fully recovered the sense, while 20 percent only partially recovered and over 2 percent did not recover at all. That amounted to almost 28 million Americans potentially left with a decreased sense of smell after COVID infection.

https://medicalxpress.com/news/2023-06-millions-patients-full-recovery-covid.html

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New onset of hypertension

was detected in 32.3% of patients(30-74y) at one-year follow-up post-COVID-19 disease recovery. Furthermore severe inflammation at admission and severe CT severity score were positively associated with the development of this new onset of hypertension on follow-up(Single center retro prospective observational study) “Incidence and predictors of development of new onset hypertension post COVID-19 disease” https://sciencedirect.com/science/articl

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Other:

Candida auris

Candida auris (C auris), which is spreading at an alarming rate in health care facilities and is now considered an “urgent antimicrobial resistance threat.”¹

...NYC healthcare facilities:  6.9% of new patients tested were positive for C auris.colonization^{5  ...}Risk factors for C auris infection include recent surgery, obesity, immunosuppression, diabetes, use of broad-spectrum antibiotics and antifungals, presence of tracheostomies, PEG tubes, and ventilators.^6,7,8 Long-term usage of broad-spectrum antibiotics can also be a risk factor for acquiring C auris infection.^6,7 Recent studies illustrate that the 30-day mortality of infected patients in an ICU was 31%.⁸

https://www.infectioncontroltoday.com/view/special-report-on-candida-auris-an-emerging-drug-resistant-fungal-threat