H5N1

Infectivity of exhaled SARS-CoV-2 aerosols is sufficient to transmit covid-19 within minutes

Via Scientific Reports: Infectivity of exhaled SARS-CoV-2 aerosols is sufficient to transmit covid-19 within minutes. The case for continued masking and improved ventilation seems inarguable. The abstract:

Exhaled SARS-CoV-2-containing aerosols contributed significantly to the rapid and vast spread of covid-19. However, quantitative experimental data on the infectivity of such aerosols is missing. Here, we quantified emission rates of infectious viruses in exhaled aerosol from individuals within their first days after symptom onset from covid-19. 

Six aerosol samples from three individuals were culturable, of which five were successfully quantified using TCID50. The source strength of the three individuals was highest during singing, when they exhaled 4, 36, or 127 TCID50/s, respectively. 

Calculations with an indoor air transmission model showed that if an infected individual with this emission rate entered a room, a susceptible person would inhale an infectious dose within 6 to 37 min in a room with normal ventilation. 

Thus, our data show that exhaled aerosols from a single person can transmit covid-19 to others within minutes at normal indoor conditions.

How covid-19 spreads: Narratives, counter narratives, and social dramas

Via The BMJ: How covid-19 spreads: narratives, counter narratives, and social dramas. The key points:

• A flawed narrative that SARS-CoV-2 was transmitted by droplets rather than being airborne became entrenched early in the pandemic 

• Measures aimed at an assumed droplet pathogen (handwashing, surface cleansing, physical distancing) were over-emphasised 

• Measures to reduce airborne transmission (improving indoor air quality, reducing indoor crowding and time spent indoors, and high-grade respiratory protection) were under-emphasised 

• UK policy makers seemed to favour narratives from a narrow group of scientific advisers 

• Consequences included care home deaths, mission critical delays in public masking, and avoidable infections of healthcare workers

How long is COVID infectious? What scientists know so far

Via Nature.com: How long is COVID infectious? What scientists know so far. Excerpt:

When the US Centers for Disease Control and Prevention (CDC) halved its recommended isolation time for people with COVID-19 to five days back in December, it said that the change was motivated by science. Specifically, the CDC said that most SARS-CoV-2 transmission occurs early in the course of the illness, in the one to two days before the onset of symptoms and for two to three days after.  

Many scientists disputed that decision then and they continue to do so. Such dissent is bolstered by a series of studies confirming that many people with COVID-19 remain infectious well into the second week after they first experience symptoms. Reductions in the length of the recommended isolation period — now common around the world — are driven by politics, they say, rather than any reassuring new data. 

 “The facts of how long people are infectious for have not really changed,” says Amy Barczak, an infectious-disease specialist at Massachusetts General Hospital in Boston. “There is not data to support five days or anything shorter than ten days [of isolation].” Barczak’s own research, published on the medRxiv preprint server, suggests that one-quarter of people who have caught the Omicron variant of SARS-CoV-2 could still be infectious after eight days.  

A numbers game  

Although the question is simple — for how long is someone with COVID-19 contagious? — experts caution that the answer is complicated. “We always think of it as a black and white thing … if somebody’s infectious or not infectious — but in reality, it’s a numbers game and a probability,” says Benjamin Meyer, a virologist at the University of Geneva in Switzerland. 

And that numbers game has shifting rules and baselines. Emerging variants, vaccination and varying levels of natural immunity provoked by previous infection can all influence how quickly someone can clear the virus from their system, Meyer says, and this ultimately dictates when they stop being infectious.  

Behavioural factors matter as well. People who feel unwell tend to mix less with others, he adds, so the severity of someone’s symptoms can influence how likely they are to infect others.

New type of ultraviolet light makes indoor air as safe as outdoors

Via Columbia University Irving Medical Center: New Type of Ultraviolet Light Makes Indoor Air as Safe as Outdoors. Excerpt:

A new type of ultraviolet light that is safe for people took less than five minutes to reduce the level of indoor airborne microbes by more than 98%, a joint study by scientists at Columbia University Vagelos College of Physicians and Surgeons and in the U.K. has found. Even as microbes continued to be sprayed into the room, the level remained very low as long as the lights were on.  

The study suggests that far-UVC light from lamps installed in the ceiling could be a highly effective passive technology for reducing person-to-person transmission of airborne-mediated diseases such as COVID and influenza indoors, and lowering the risk of the next pandemic.   

“Far-UVC rapidly reduces the amount of active microbes in the indoor air to almost zero, making indoor air essentially as safe as outdoor air,” says David Brenner, PhD, director of the Center for Radiological Research at Columbia University Vagelos College of Physicians and Surgeons and co-author of the study. “Using this technology in locations where people gather together indoors could prevent the next potential pandemic.”  

The study was published March 23 in the journal Scientific Reports, a Nature journal.  

“Far-UVC light is simple to install, it’s inexpensive, it doesn’t need people to change their behavior, and evidence from multiple studies suggests it may be a safe way to prevent the transmission of any virus, including the COVID virus and its variants, as well as influenza and also any potential future pandemic viruses,” Brenner says. 

What is far-UVC light?  

Disinfecting indoor air with far-UVC light is a new approach to safely and efficiently destroy airborne viruses in occupied spaces, including the viruses that cause COVID and influenza.  

Scientists have known for decades that a type of ultraviolet light known as UVC light rapidly kills microbes, including bacteria and viruses. But conventional germicidal UVC light cannot be used directly to destroy airborne viruses in occupied indoor spaces because it is a potential health hazard to the skin and eyes.  

About a decade ago, Columbia University scientists proposed that a different type of UVC light, known as far-UVC light, would be just as efficient at destroying bacteria and viruses but without the safety concerns of conventional germicidal UVC.  

Far-UVC light has a shorter wavelength than conventional germicidal UVC, so it can’t penetrate into living human skin cells or eye cells. But it is equally efficient at killing bacteria and viruses, which are much smaller than human cells.  

In the past decade, many studies around the world have shown that far-UVC is both efficient at destroying airborne bacteria and viruses without causing damage to living tissue. But until now these studies had only been conducted in small experimental chambers, not in full-sized rooms mimicking real-world conditions.

Helen Branswell talks with Mike Ryan

Via STAT, Helen Branswell interviews Mike Ryan, head of WHO's health emergencies program: WHO official weighs in on Covid, vaccines, and mistakes that were made. This excerpt is a key part of an interview you should read in its entirety:

Are there things you wish the world had done differently from the jump? Where did we make our biggest mistakes? 

This interview could go on for a while.        

The biggest collective failing has been that we’ve underestimated this microbe. We’ve always made judgments assuming the best-case scenario. And I’m not one for assuming the worst-case scenarios as a modus operandi, because otherwise, you can strangle society. But I think at every opportunity we’ve seem to have taken the best-case scenario as the basis for our policy. And this virus, I think, has sequentially exploited that.  

In the end, the virus doesn’t have a brain. It’s just, from an evolutionary point of view, exploiting opportunities. And we seem to have consistently and persistently given it the opportunity.  

There’s been tremendous social, economic, and political pressure to go back to normal.   

Time and time again governments have tried to get back to normal and have overshot that runway by opening up too early. Releasing restrictions too early. They haven’t really convinced people or empowered people to continue with these basic measures to reduce the risk of infection. I think that’s been a problem, the whole way through the pandemic.  

I don’t mean getting rid of lockdowns. To me lockdowns have been last resort measures in most cases. Many countries in the East have managed to forgo lockdowns. But they’ve maintained quite strict measures in terms of mask wearing, in terms of crowds, in terms of testing and other stuff. So they’ve taken a much more comprehensive, layered strategy. They’ve maintained an intensity of control measures without ever going for full lockdown, without ever going for full open. They’ve taken the corner without under- or over-steering.  They’ve gotten people to buy into the idea that it’s going to take a long time and it’s going to have to be a sustained effort. I think if everyone had done that maybe we’d be in a better place.   

But I think for me just personally as a public health physician, the biggest tragedy has been the vaccine equity issue. It really has been horrific. Horrific. The world just has not ever come to terms with the fact that vaccinating the most vulnerable people first would have been a better bet, not only epidemiologically but just from an equity perspective.   

The idea of coherence and coordination and solidarity — these are all lovely words. But it’s very hard to deliver that in societies that don’t trust governments, [don’t buy into] that social contract, that inherent trust that a community should have in its government to say, “Yes, you are there to protect me.”  

What’s shocked me most in this pandemic has been that absence or loss of trust.  

It’s staggering to read about public health personnel quitting their jobs, being subjected to death threats during a pandemic. They’re facing hatred and vitriol from the people they’re trying to protect.   

It’s tragic. And it’s tragic to think that there are millions of people right now in the Northern Hemisphere who are not vaccinated because they don’t believe their government. Whatever the reasons for that are, whether it’s because governments perform poorly in building that trust, or whether they’ve been actively undermined by misinformation and by other things, historians and social historians will be talking about that one for decades.   

If we’re looking at pandemic preparedness for the future it’s not all going to be about technology and the machines that go ping and surveillance systems and AI and all of this stuff. We need a social solution for future pandemics, much more than we need a technological solution. Because we’re dealing with a fractured world, fractured communities. We’re dealing with a breach and prolonged breakdown in trust.

I shudder to think of going into a more severe pandemic with that level of community distrust. It has had a real negative impact on people’s awareness and willingness to sustain measures. Because they can constantly find lots of material and reasons not to do what they’re being asked to do, because there’s so much out there telling them that what’s going on there is a government conspiracy, what’s happening is hurting them.

‘Black fungus’ is creating a whole other health emergency for Covid-stricken India

Via The Guardian: ‘Black fungus’ is creating a whole other health emergency for Covid-stricken India. Excerpt:

Covid-19 has killed millions around the world, but for some who are lucky enough to survive the infection, the nightmare is not over: adding insult to injury are deadly fungal infections that follow in the wake of the virus. Making matters worse, inequities that long predated the pandemic have left some countries without the capacity to combat these serious infections. 

In India, a fungal infection called mucormycosis has emerged in patients with Covid-19. This infection is caused by a group of fungi that are everywhere on the planet. In fact, all of us are probably inhaling spores of these fungi every day, but these are rapidly controlled by our immune systems. Rarely, our defences are breached, and the fungus takes hold, with devastating consequences. After establishing itself in the nose and sinuses, it begins to invade the tissue of the face, the jaw, the eyes and brain, blocking blood flow and causing tissue death. It is the black discoloration of dead tissue that conferred upon this mould its fearsome moniker in the Indian media: “the black fungus”.

Although the fungi are ubiquitous, mucormycosis is usually rare, and most specialists around the world will see fewer than a dozen cases in their entire careers. Even before the pandemic, rates of mucormycosis in India were estimated to be about 70 times higher than in the rest of the world. 

Even so, the tsunami of cases occurring in the wake of Covid-19 is of an unimaginable scale. More than 11,700 people were reported by a government minister to be receiving care for mucormycosis on 25 May. Two states, Maharashtra and Gujarat, have confirmed more than 5,500 cases. Whereas a large referral hospital in London might see three or four cases a year, some Indian hospitals are caring for more than 500 patients with mucormycosis right now. 

Mucormycosis cases in Covid-19 patients have also been linked to poorly controlled diabetes and therapeutic steroids, a triad of risk factors some have dubbed “the unholy trinity”. Although steroids can be lifesaving in Covid-19 patients needing supplemental oxygen, they are a double-edged sword: they weaken the immune system that normally keeps fungi we inhale at bay. 

Undisciplined prescribing is likely to be playing a major role in driving the epidemic: one study at 16 Indian hospitals found that nearly two in three steroid prescriptions for Covid-19 patients were inappropriate (they were either used in patients who weren’t sick enough to warrant them, or the dose was too high). Lack of access to oxygen may have resulted in doctors overcompensating by prescribing higher-than-recommended doses. 

Additionally, rates of diabetes have been increasing in India, and high blood sugars further weaken the immune system and increase the growth of fungi in the body. High blood sugars are also a well-known side-effect of steroids, particularly in diabetic or prediabetic patients, and overstretched healthcare workers have been unable to adequately monitor blood sugar levels of Covid-19 patients on crowded wards. 

The confluence of these risk factors, plus higher-than-average background rates of mucormycosis, high numbers of spores in both indoor and outdoor environments, and the lack of hospital infection-control resources (like efficient air particle filters in ICU rooms, standard in resource-rich settings to filter out airborne spores) have allowed the fungus to run amok.

Investigation of a severe SARS-CoV-2 outbreak in a long-term care home early in the pandemic

Via CMAJ: Investigation of a severe SARS-CoV-2 outbreak in a long-term care home early in the pandemic. The abstract:

BACKGROUND: The implementation of outbreak management measures has decreased the frequency and severity of SARS-CoV-2 outbreaks in Ontario long-term care homes. We describe the epidemiological and laboratory data from one of the first such outbreaks in Ontario to assess factors associated with its severity, and the impact of progressive interventions for infection control over the course of the outbreak. 

METHODS: We obtained line list and outbreak data from the public health unit to describe resident and staff cases, severity and distribution of cases over time and within the outbreak facility. Where available, we obtained data on laboratory specimens from the Public Health Ontario Laboratory and performed whole genome sequencing and phylogenetic analysis of viral specimens from the outbreak. 

RESULTS: Among 65 residents of the long-term care home, 61 (94%) contracted SARS-CoV-2, with a case fatality rate of 45% (28/61). Among 67 initial staff, 34 (51%) contracted the virus and none died. When the outbreak was declared, 12 staff, 2 visitors and 9 residents had symptoms. Resident cases were located in 3 of 4 areas of the home. Phylogenetic analysis showed tight clustering of cases, with only 1 additional strain of genetically distinct SARS-CoV-2 identified from a staff case in the third week of the outbreak. No cases were identified among 26 new staff brought into the home after full outbreak measures were implemented. 

INTERPRETATION: Rapid and undetected viral spread in a long-term care home led to high rates of infection among residents and staff. Progressive implementation of outbreak measures after the peak of cases prevented subsequent staff cases and are now part of long-term care outbreak policy in Ontario. 

The order is to avoid lockdown, says Brazil's health minister

Via DW Brasil: The order is to avoid lockdown, says Brazil's health minister. The Google translation, lightly edited:

While Brazil continues to reports record counts of deaths by covid-19, the Minister of Health, Marcelo Queiroga, affirmed this Saturday (03/04) that "the order is to avoid the lockdown" in the country, but for that the country needs to do your "homework". 

"We need to organize ourselves so that we avoid extreme measures and we are able to ensure that people continue to work, earning their wages and income, making the economy work, leaving these extreme measures for another case. Avoiding lockdown is the order, but we have to do our homework, "said the minister at a news conference. 

According to Queiroga, this duty belongs not only to the federal, state and municipal governments, but "to each of the citizens". He referred to preventive measures against the advancement of covid-19, such as the use of masks and physical distancing. 

The statements were made after the minister's first meeting with the director general of the World Health Organization (WHO), Tedros Adhanom, in which the director of the Pan American Health Organization (PAHO) in Brazil, Socorro Gross, also participated. 

Queiroga also said that the ministry is working on a protocol to guide the population using public transport "to do this in a more orderly manner, in order to prevent the closure of our economy". The intention is to avoid crowding, he said. 

As much as he resists the idea of ​​a lockdown, following the posture of President Jair Bolsonaro, Queiroga defended the importance of preventive measures against the covid-19, in contrast to the speech of the head of state, who during the pandemic despised such actions. 

This Saturday, the minister made an appeal for the population to wear masks, always clean their hands, practice social distance and avoid crowds. 

"I take the opportunity, at this Easter time, to ask each Brazilian to wear a mask. Take advantage of the holiday so as not to make crowds, it is essential. We often see the population having parties, without masks. This is not appropriate, we need each one to collaborate," declared Queiroga. 

"The population's adherence is not easy. As much as we talk, you [journalists] talk every day on TV, and we were unable to make the population adhere to these measures that seem simple, but are efficient", he added. 

"We are against closing everything" 

Social isolation, the closure of the economy and restrictions on the movement of people are promoted by international health authorities as some of the most efficient measures to combat the coronavirus, and have been implemented by most governments around the world. 

However, against the rest of the world, Bolsonaro minimized the severity of the disease and attacked these restrictive measures throughout the pandemic, preferring instead to bet on drugs that have proven ineffective against the virus, such as chloroquine. 

This Saturday, the president took a walk alongside the new defense minister, Walter Braga Netto, in which he appears without a mask during a live broadcast on social networks. On a visit to the Casa de Maria Beth Myriam, in Brasília, Bolsonaro ate soup and again criticized rules imposed by governors in favor of distancing. "We are against closing everything." 

Brazil is currently experiencing the worst moment of the covid-19 epidemic, with successive records of daily deaths and collapsing hospitals. Last week, the country recorded 3,869 deaths in just 24 hours, the highest number since the beginning of the crisis. In all, more than 330 thousand people have died in the country as a result of the disease.

With all eyes on Covid-19, drug-resistant infections crept in

Via The New York Times: With All Eyes on Covid-19, Drug-Resistant Infections Crept In.

As Covid-19 took hold over the last year, hospitals and nursing homes used and reused scarce protective equipment — masks, gloves, gowns. This desperate frugality helped prevent the airborne transfer of the virus. 

But it also appears to have helped spread a different set of germs — drug-resistant bacteria and fungi — that have used the chaos of the pandemic to grow opportunistically in health care settings around the globe. 

These bacteria and fungi, like Covid-19, prey on older people, the infirm and those with compromised immune systems. They can cling tenaciously to clothing and medical equipment, which is why nursing homes and hospitals before the pandemic were increasingly focused on cleaning rooms and changing gowns to prevent their spread. 

That emphasis all but slipped away amid an all-consuming focus on the coronavirus. In fact, experts warn, the changes in hygiene and other practices caused by the Covid-19 fight are likely to have contributed to the spread of these drug-resistant germs.  

“Seeing the world as a one-pathogen world is really problematic,” said Dr. Susan S. Huang, an infectious disease specialist at the University of California at Irvine Medical School, noting that the nearly singular focus on the pandemic appears to have led to more spread of drug-resistant infection. “We have every reason to believe the problem has gotten worse.”  

A few data points reinforce her fears, including isolated outbreaks of various drug-resistant infections in Florida, New Jersey and California, as well as in India, Italy, Peru and France. Overall figures have been hard to track because many nursing homes and hospitals simply stopped screening for the germs as resources were diverted to Covid-19.  

When even modest screening picked up again early in the summer, the results suggested that certain drug-resistant organisms had taken root and spread. Particularly troublesome have been growing case counts of a fungus called Candida auris, which authorities had tried to fight before the pandemic with increased screening, isolation of infected patients and better hygiene.

COVID-19 infection gives some immunity, but virus can still be spread, study finds

Via Reuters: COVID-19 infection gives some immunity, but virus can still be spread, study finds. Excerpt:

LONDON (Reuters) - People who have had COVID-19 are highly likely to have immunity to it for at least five months, but there is evidence that those with antibodies may still be able to carry and spread the virus, a study of British healthcare workers has found.   

Preliminary findings by scientists at Public Health England (PHE) showed that reinfections in people who have COVID-19 antibodies from a past infection are rare - with only 44 cases found among 6,614 previously infected people in the study.  

But experts cautioned that the findings mean people who contracted the disease in the first wave of the pandemic in the early months of 2020 may now be vulnerable to catching it again. 

They also warned that people with so-called natural immunity - acquired through having had the infection - may still be able carry the SARS-CoV-2 coronavirus in their nose and throat and could unwittingly pass it on. 

“We now know that most of those who have had the virus, and developed antibodies, are protected from reinfection, but this is not total and we do not yet know how long protection lasts,” said Susan Hopkins, senior medical adviser at PHE and co-leader of the study, whose findings were published on Thursday.