New York:

The Central Intelligence Agency has assessed that the COVID-19 pandemic is “more likely” to have emerged from a lab rather than from nature, an agency spokesperson said on Saturday.

The agency had for years said it could not conclude whether COVID-19 was the result of a lab incident or it originated in nature. But in the final weeks of the Biden administration, former CIA Director William Burns asked CIA analysts and scientists to make a clear determination, stressing the pandemic’s historical significance, according to a senior US official.

The CIA says it has “low confidence” in its assessment that a “research-related origin of the COVID-19 pandemic is more likely” and notes in its statement that both scenarios – lab origin and natural origin – remain plausible.

The Chinese embassy in Washington did not immediately respond to a request for comment.

It was unclear the extent to which the agency has collected new intelligence on COVID-19’s origins and whether that new evidence was used to formulate the latest assessment.

China’s government says it supports and has taken part in research to determine COVID-19’s origin, and has accused Washington of politicizing the matter, especially because of efforts by U.S. intelligence agencies to investigate.

Beijing has said claims that a laboratory leak likely caused the pandemic have no credibility.

In an interview with Breitbart following his confirmation by the U.S. Senate on Friday, CIA Director John Ratcliffe said one of his first priorities was getting his agency to make a public assessment on the pandemic’s origins.

“That’s a day-one thing for me,” he said. “I’ve been on record as you know in saying I think our intelligence, our science, and our common sense all really dictate that the origins of COVID was a leak at the Wuhan Institute of Virology.”

(Reporting by Erin Banco; Editing by Daniel Wallis)

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

New Delhi:

Women might be at a 31 per cent higher risk of developing long Covid compared to men, with those aged 40-55 years likely to be at most risk, a study has found.

Among the women aged 40-55 years, the risk of long Covid was found to be even higher — 42 per cent in menopausal women and 45 per cent in non-menopausal women — the results of the ‘RECOVER’ trial, published in The Journal of the American Medical Association (JAMA) Network Open showed.

Long Covid is estimated to affect about a third of those once infected with Covid-19, with symptoms, such as fatigue and brain fog, persisting well beyond the acute recovery period. The condition, including its causes and treatments, continues to be studied around the world.

Researchers, led by those at The University of Texas, US, followed more than 12,200 people (73 per cent of women), who reported their symptoms while responding to questionnaires at their first study visit at least six months after infection. The participants were enrolled between October 2021, and July 2024.

The trial showed that all women, except those aged 18-39 years, had a 31 per cent higher risk of long Covid — regardless of race, ethnicity, Covid variant and severity of the viral infection.

The study helps identify risk factors for long Covid critical for preventing and treating the often debilitating disease, according to lead researcher Thomas Patterson, a professor of medicine and chief of the division of infectious diseases, school of medicine, The University of Texas.

The researchers added that biological processes contributing to sex-specific differences of long Covid need to be identified that can help develop targeted drugs and improve management of the condition.

“These findings show that patients and health care teams should consider the differences in long COVID risk as it relates to sex assigned at birth,” corresponding author Dimpy Shah, an assistant professor of population health sciences at The University of Texas, said.

“Understanding these differences can help us recognise and treat patients with long Covid more effectively,” Shah said.

While previous studies have shown women to have a tendency for post-viral and autoimmune conditions, it is not clear if the same is true for long Covid, especially within different age groups, the researchers said.

“This study gives us new knowledge and builds on other studies that also looked at sex assigned at birth and long Covid,” Shah said.

“Because of the size of the RECOVER study and the diversity of participants, we had a special opportunity to look at sex assigned at birth while also considering things like vaccination status, autoimmune disease, diabetes, BMI and Covid variant,” the corresponding author said.

(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)

A laboratory technician prepares COVID-19 patient samples for semi-automatic testing at Northwell Health Labs, Wednesday, March 11, 2020, in Lake Success, N.Y.
| Photo Credit: AP

Five years since Covid-19 started upending the world, the virus is still infecting and killing people across the globe — though at far lower levels than at the height of the pandemic.

Here is the current state of the play.

Still with us

Around 777 million Covid cases and more than seven million deaths have been officially recorded since the first infections emerged in December 2019, according to the World Health Organization (WHO).

However, the true toll is believed to be far higher.

The pandemic also crippled health systems, crashed economies and sent the populations of many countries into lockdown.

In the second half of 2022, infection and death rates tumbled due to growing immunity from vaccinations or prior infection. The virus also mutated to become less severe.

In May 2023, the WHO declared the emergency phase of the pandemic was over.

Since then, the virus seems to have gradually become endemic, according to experts, with occasional resurgences similar to the flu — although less seasonal.

It has also largely receded from the public eye.

“The world wants to forget this pathogen that is still with us, and I think people want to put Covid in the past as if it’s over — and in many respects pretend it didn’t happen — because it has been so traumatic,” WHO pandemic preparedness director Maria Van Kerkhove said last month.

From October to November last year, there were more than 3,000 deaths from Covid across 27 countries, according to the WHO.

More than 95 percent of official Covid deaths were recorded between 2020 and 2022.

Variants

Since the Omicron variant emerged in November 2021, a succession of its subvariants have been replacing each other as the dominant strain around the world.

At the moment, the Omicron variant KP.3.1.1 is the most common.

The rising XEC is the only “variant under monitoring” by the WHO, though the United Nations agency rates its global health risk as low.

None of the successive Omicron subvariants have been noticeably more severe than others, although some experts warn it is not out of the question that future strains could be more transmissible or deadly.

Vaccines and treatments

Vaccines were developed against Covid in record time and they proved a powerful weapon against the virus, with more than 13.6 billion doses administered worldwide so far.

However rich countries bought up a large portion of the early doses, creating unequal distribution across the world.

Booster shots updated for the JN.1 Omicron subvariant are still recommended in some nations, particularly for at-risk groups such as the elderly.

However, the WHO has said most people — including the elderly — have not kept up with their booster shots.

Even among healthcare workers, the booster uptake rate was below one percent in 2024, according to the WHO.

Long Covid

Millions of people have been affected by long Covid, a still little-understood condition that lasts months after the initial infection.

Common symptoms include tiredness, brain fog and shortness of breath.

About six percent of people infected by coronavirus develop long Covid, the WHO said last month, adding that the condition “continues to pose a substantial burden on health systems”.

Much about long Covid remains unknown. There are no tests or treatments. Multiple Covid infections seem to increase the chance of getting the condition.

Future pandemics?

Scientists have warned that another pandemic will strike sooner or later, urging the world to learn the lessons of Covid and prepare for next time.

Attention has recently focussed on bird flu (H5N1), particularly after the United States reported on Monday the first human death from the virus.

The patient in Louisiana had underlying medical conditions and contracted H5N1 after being exposed to infected birds, US health authorities said, emphasising there was no evidence of person-to-person transmission.

Since late 2021, the WHO’s member states have been negotiating a world-first treaty on pandemic prevention, preparedness and response.

However, an agreement has remained elusive ahead of a May deadline, with a key faultline lying between Western nations and poorer countries wary of being sidelined when the next pandemic occurs.

The Covid pandemic also saw a massive increase in scepticism and misinformation about vaccines.

Experts have warned about the prospect of having vaccine sceptic and conspiracy theorist Robert F. Kennedy Jr. — US President-elect Donald Trump’s pick for health secretary — in charge of the US response to a possible pandemic threat over the next four years.

While it’s one thing to acknowledge the limits to our knowledge of the microbial soup we live in, more recent attention has focused on how we might systematically approach future pandemic risks.

Former US Secretary of Defense Donald Rumsfeld famously talked about “known knowns” (things we know we know), “known unknowns” (things we know we don’t know), and “unknown unknowns” (the things we don’t know we don’t know).

Although this may have been controversial in its original context of weapons of mass destruction, it provides a way to think about how we might approach future pandemic threats.

Influenza: a ‘known known’

Influenza is largely a known entity; we essentially have a minor pandemic every winter with small changes in the virus each year. But more major changes can also occur, resulting in spread through populations with little pre-existing immunity. We saw this most recently in 2009 with the swine flu pandemic.

However, there’s a lot we don’t understand about what drives influenza mutations, how these interact with population-level immunity, and how best to make predictions about transmission, severity and impact each year.

The current H5N1 subtype of avian influenza (“bird flu”) has spread widely around the world. It has led to the deaths of many millions of birds and spread to several mammalian species including cows in the United States and marine mammals in South America.

Human cases have been reported in people who have had close contact with infected animals, but fortunately there’s currently no sustained spread between people.

While detecting influenza in animals is a huge task in a large country such as Australia, there are systems in place to detect and respond to bird flu in wildlife and production animals.

It’s inevitable there will be more influenza pandemics in the future. But it isn’t always the one we are worried about.

Attention has been focused on avian influenza since 1997 when an outbreak in birds in Hong Kong caused severe disease in humans. However the subsequent pandemic in 2009 originated in pigs in central Mexico.

Coronaviruses: an ‘unknown known’

Although Rumsfeld didn’t talk about “unknown knowns”, coronaviruses would be appropriate for this category. We knew more about coronaviruses than most people might have thought before the COVID pandemic.  

We’d had experience with severe acute respiratory syndrome (SARS) and Middle Eastern respiratory syndrome (MERS) causing large outbreaks. Both are caused by viruses closely related to SARS-CoV-2, the coronavirus that causes COVID. While these might have faded from public consciousness before COVID, coronaviruses were listed in the 2015 WHO list of diseases with pandemic potential.

Previous research into the earlier coronaviruses proved vital in allowing COVID-19 vaccines to be developed rapidly. For example, the Oxford group’s initial work on a MERS vaccine was key to the development of AstraZeneca’s COVID-19 vaccine.

Similarly, previous research into the structure of the spike protein – a protein on the surface of coronaviruses that allows it to attach to our cells – was helpful in developing mRNA vaccines for COVID.

It would seem likely there will be further coronavirus pandemics in the future. And even if they don’t occur at the scale of COVID, the impacts can be significant. For example, when MERS spread to South Korea in 2015, it only caused 186 cases over two months, but the cost of controlling it was estimated at US$8 billion (A$11.6 billion).

The 25 viral families: an approach to ‘known unknowns’

Attention has now turned to the known unknowns. There are about 120 viruses from 25 families that are known to cause human disease. Members of each viral family share common properties and our immune systems respond to them in similar ways.

An example is the flavivirus family, of which the best-known members are yellow fever virus and dengue fever virus. This family also includes several other important viruses, such as Zika virus (which can cause birth defects when pregnant women are infected) and West Nile virus (which causes encephalitis, or inflammation of the brain).

The WHO’s blueprint for epidemics aims to consider threats from different classes of viruses and bacteria. It looks at individual pathogens as examples from each category to expand our understanding systematically.

The US National Institute of Allergy and Infectious Diseases has taken this a step further, preparing vaccines and therapies for a list of prototype pathogens from key virus families. The goal is to be able to adapt this knowledge to new vaccines and treatments if a pandemic were to arise from a closely related virus.

Pathogen X, the ‘unknown unknown’

There are also the unknown unknowns, or “disease X” – an unknown pathogen with the potential to trigger a severe global epidemic. To prepare for this, we need to adopt new forms of surveillance specifically looking at where new pathogens could emerge.

In recent years, there’s been an increasing recognition that we need to take a broader view of health beyond only thinking about human health, but also animals and the environment. This concept is known as “One Health” and considers issues such as climate change, intensive agricultural practices, trade in exotic animals, increased human encroachment into wildlife habitats, changing international travel, and urbanisation.

This has implications not only for where to look for new infectious diseases but also for how we can reduce the risk of “spillover” from animals to humans. This might include targeted testing of animals and people who work closely with animals. Currently, testing is mainly directed towards known viruses, but new technologies can look for as yet unknown viruses in patients with symptoms consistent with new infections.

We live in a vast world of potential microbiological threats. While influenza and coronaviruses have a track record of causing past pandemics, a longer list of new pathogens could still cause outbreaks with significant consequences.

Continued surveillance for new pathogens, improving our understanding of important virus families, and developing policies to reduce the risk of spillover will all be important for reducing the risk of future pandemics.

This article is part of a series on the next pandemic.

Allen Cheng, Professor of Infectious Diseases, Monash University 

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Scientists have warned that a “more contagious” variant of Covid-19, dubbed XEC, is spreading more rapidly across Europe and could soon become the dominant strain. According to the BBC, the new variant was first identified in Germany in June, and since then, the XEC variant has emerged in the UK, US, Denmark and several other countries. Experts have said that the new variant, a sublineage of the omicron variant, has some new mutations that might help it spread this autumn, although vaccines should still help prevent severe cases. 

The XEC variant is a hybrid of the earlier omicron subvariants KS.1.1 and KP.3.3, which is currently dominant in Europe. So far, 500 samples from 27 countries, including Poland, Norway, Luxembourg, Ukraine, Portugal and China, have been found to contain XEC, The Independent reported. Experts point to strong growth of the variant in Denmark, Germany, the UK, and the Netherlands.

Professor Francois Balloux, Director of the Genetics Institute at University College London, told BBC that although XEC has a “slight transmission advantage” over other recent Covid variants, vaccines should still offer good protection. But he also added that XEC may become the dominant subvariant over the winter. 

Also Read | “Wear Proper Undergarments”: Delta Airlines’ New Memo For Flight Attendants

Director of the Scripps Research Translational Institute, in California, Eric Topol said XEC is “just getting started”. “And that’s going to take many weeks, a couple months, before it really takes hold and starts to cause a wave,” he said. 

“XEC is definitely taking charge. That does appear to be the next variant. But it’s months off from getting into high levels,” said Mr Topol. 

Symptoms of XEC Covid

The symptoms of the XEC variant are similar to those of previous Covid variants, including fever, sore throat, cough, loss of sense of smell, loss of appetite, and body aches. 

But since it is still only a sub-family of the same omicron lineage, experts say keeping up to date with vaccines and booster shots would offer sufficient protection against severe illness and hospitalisation.

Separately, the US Centres for Disease Control and Prevention (CDC) has also advised people to practise good hygiene and take steps for cleaner air.

Moreover, researchers have called for monitoring the XEC more closely to better understand its symptoms. 

Geneva:

Covid-19 is still killing around 1,700 people a week around the world, the World Health Organization said Thursday, as it urged at-risk populations to keep up with their vaccinations against the disease.

WHO director-general Tedros Adhanom Ghebreyesus sounded a warning on declining vaccine coverage.

Despite the continued death count, “data show that vaccine coverage has declined among health workers and people over 60, which are two of the most at-risk groups,” the UN health agency’s chief told a press conference.

“WHO recommends that people in the highest-risk groups receive a Covid-19 vaccine within 12 months of their last dose.”

More than seven million Covid deaths have been reported to the WHO, though the true count of the pandemic is thought to be far higher.

Covid-19 also shredded economies and crippled health systems.

Tedros declared an end to Covid-19 as an international public health emergency in May 2023, more than three years on from when the virus was first detected in Wuhan, China, in late 2019.

The WHO has urged governments to maintain virus surveillance and sequencing, and to ensure access to affordable and reliable tests, treatments and vaccines.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

A worker fumigating a private building surroundings to control mosquitoes and to prevent spread of dengue. File
| Photo Credit: K. Bhagya Prakash

Can the dengue virus beat the coronavirus and is it why the early wave of the pandemic in 2020 resulted in fewer COVID deaths or severe infections compared to Europe or North America where dengue is not endemic? Research from the CSIR-Indian Institute of Chemical Biology, Kolkata hints at these intriguing possibilities following an analysis of antibodies from people infected with dengue and testing them against a kind of coronavirus called murine hepatitis virus (mouse coronavirus). In research settings, this virus — being part of the same family of human coronaviruses — is considered a good surrogate to study the behaviour of the coronavirus strains that infected people during the pandemic.

Their results, published in the peer-reviewed Journal of Medical Virology this week, suggest that the antibodies following a dengue infection were able to ‘neutralise’ these coronavirus. For their analysis, the scientists relied on a combination of computer-modelling studies as well as cell-culture studies, the latter demonstrating how antibodies from dengue were able to engulf and bind the coronavirus proteins.

However, this protective effect did not necessarily expand to all coronavirus variants.

These latest studies build on the lab’s work from 2020 that blood tests specific to check for dengue sometimes led to a positive SARS-CoV-2 test.

“We experimentally demonstrated that serum samples from dengue patients have the potential to bind to and “mask” the surface of several coronaviruses, including SARS-CoV-2. We performed “virus neutralization” tests in cell cultures and showed that such “masking” by dengue antibodies can indeed, block coronavirus entry into susceptible cells,” Dr. Subhajit Biswas, Principal Scientist and the main author of the study, told The Hindu.

The dengue family of viruses are different from the coronavirus family and hence infection from one, in normal circumstances, is not expected to protect against the other. What is known about dengue is that there are four major serotypes, or strains, that cause dengue infections. Strains Denv-1 and Denv-2 are the most common in India. However, being infected with one does not protect against the other and, in fact, a re-infection involving a different strain can be more dangerous — a phenomenon called antibody-dependent enhancement (ADE) in dengue. Whether the prevalence of dengue in dengue-endemic countries of Southeast Asia may be triggering newer mutations in the coronavirus is a factor that needs to be investigated more extensively, the authors suggest in their study.

That the early stages of the pandemic saw a decline in dengue in India has been independently reported. The National Vector Borne Disease Control Programme of India reported a sharp decline of 75% (39,419 versus 1,57,315) in dengue incidence during 2020 as compared with 2019. “The possible reasons for this reduction could be lower transmission of the vector, less exposure due to COVID-19 lockdown, and, potentially, a disparity in the reported data possibly due to underdiagnosis or underreporting because of increased attention to the COVID-19 pandemic,” said a 2021 study in the American Journal of Tropical Medicine and Hygeine.

“In this paper, we provided several pieces of experimentally obtained evidence that pre-existing dengue immunity might have played some protective role in reducing the COVID severity and mortality in dengue-prone regions like Southeast Asia compared to regions where dengue does not occur frequently, like Europe and North America. Perhaps this is why, historically, human coronaviruses have been rarely encountered as a causative agent of “severe acute respiratory infections, SARI” from India, highly endemic for dengue virus,” he added.

The dilemma was whether the cross-reactive antibodies would provide partial protection against severe dengue infection or lead to increased severity due to the well-known phenomenon of antibody-dependent enhancement seen in dengue.  We hypothesize that the presence of antibodies to SARS-CoV-2 might decrease the severity of dengue. Larger multicentric clinical studies or population data from dengue endemic regions might help in understanding the existence of the cross-reactive, cross-protective association between these two single-stranded, positively coiled +SS RNA viruses.

“In 2020, deaths around the world rose by 10.8% compared to 2019, and in 2021, they rose by 7.5% relative to 2020.”
| Photo Credit: Reuters

COVID-19 (coronavirus) replaced stroke to become the second-leading cause of death globally in 2021, causing 94 deaths per one lakh population and slashing life expectancy by 1.6 years, an international research published in The Lancet journal has found.

“Disrupting more than three decades of consistent improvements in life expectancy and deaths, COVID-19 reversed this long-standing progress to emerge as “one of the most defining global health events of recent history,” researchers said.

“In 2020, deaths around the world rose by 10.8% compared to 2019, and in 2021, they rose by 7.5% relative to 2020. Death rates too followed a similar trend, rising by 8.1% in 2020 and an additional 5.2% in 2021,” the study estimated.

“Globally, COVID-19 and related deaths were responsible for slashing life expectancy by 1.6 years between 2019 and 2021, even as reduced deaths from infections, stroke, and of newborns, among others, had helped steadily enhance life expectancy between 1990 and 2019,” the researchers found.

“India lost 1.9 years of life expectancy due to COVID-19, resulting in a net gain of 7.9 years of life expectancy between 1990 and 2021,” the study showed. “COVID-19 had a pronounced influence on the reduction in global life expectancy that occurred,” the authors wrote.

The researchers forming the Global Burden of Disease (GBD) Causes of Death Collaborators estimated mortality and years of life lost from 288 causes of death across 204 countries and territories for every year from 1990 until 2021. Region-wise, death rates from COVID-19 were the highest in the sub-Saharan Africa.

“In Latin America and the Caribbean, it was at 271 per one lakh population and almost 200 deaths per one lakh population, respectively. The rate was the lowest in southeast Asia, east Asia, and Oceania at around 23 deaths per one lakh population,” the researchers estimated.

“The impact of COVID-19 on life expectancy was found to be wide-ranging in severity, with Andean Latin America seeing a loss of 4.9 years and the southern sub-Saharan Africa seeing a reduction of 3.4 years, to the east Asia, which witnessed almost no change,” they said in the study.

“The leading cause of death worldwide in 2021 continues to be ischaemic heart disease, as was the case in 2019 and 1990,” the researchers found. The disease is caused by a reduced blood flow to a certain body part due to clotting or constricting blood vessels.

Stroke, at the third position amongst the top five causes of death, was found to be followed by chronic obstructive pulmonary disease (COPD) at fourth, and other pandemic-related mortality at fifth. COPD is a lung condition usually seen to affect heavy smokers.

The GBD study, providing “latest comprehensive estimates of cause-specific mortality,” gives insights about the global landscape of disease before and during the first two years of the pandemic, revealing changes in disease-burden patterns that followed, according to the researchers, coordinated by the Institute for Health Metrics and Evaluation (IHME), University of Washington, U.S.

File photo used for representational purpose only.

Children infected with the Omicron variant remain infectious for three days on average after testing positive for the SARS-CoV-2 virus, according to a study.

Researchers at the University of Southern California (USC) and Stanford University in the U.S. noted that school policies that require students with COVID-19 to stay out of the classroom for five days are more than sufficient.

“We are basically saying five days is more than sufficient; public health and education leaders may consider shorter durations,” said study co-author Neeraj Sood, Director of the COVID-19 Initiative and a senior fellow at the USC Schaeffer Center.

The study, published in the journal JAMA Pediatrics, found that the median time of infectivity was three days, with 18.4% and 3.9% of children still infectious on day five and day 10, respectively.

The researchers also found no association between how long children were infectious and whether they were vaccinated, suggesting return-to-school policies may not need discriminate by vaccine or booster status.

The study seeks to inform policymakers who grapple with how long children must isolate when they contract COVID-19. Such self-isolation policies, aimed at halting the spread of the virus, can negatively interrupt children’s education.

“We want to protect other children in the school who could potentially get infected, but at the same time, we don’t want to disrupt education for the child who is infected, given the amount of disruption that’s already happened,” said Mr. Sood.

“The duration of infectivity is an important parametre into figuring out what the optimal duration of self-isolation should be,” he added.

The researchers partnered with a virus testing company and examined nasal swabs from 76 children in Los Angeles County who were between the ages of seven and 18 and tested positive for COVID-19.

Survey participants provided samples during five home visits over a 10-day period and samples were examined in a lab to find evidence of cell death, a sign of infectivity. All participants were infected with the Omicron variant of COVID-19.

“We wanted to capture how infectivity changed over the 10-day window,” said study lead author Nikhilesh Kumar, a Doctor of Medicine student at the USC Keck School of Medicine.

The findings are consistent with previous research on adults who contracted the Omicron variant, which showed no association between vaccination status and time of infectivity.

“That research, published in the New England Journal of Medicine, showed adults with Omicron were infected for a slightly longer duration, with a median time of five days,” the authors noted.

The team called for further research so that policymakers can consider adjusting the time students must stay out of the classroom.

Many tiny organisms including bacteria, fungi and viruses normally live on our bodies, and even inside us. These are called the microbiome. The large number of these organisms living in the gastrointestinal tract are collectively known as the gut microbiome.

Increasingly the gut microbiome is recognised as playing a large part in health and disease, particularly relating to human physiology, metabolism and immune function.

There are now more than 700 published papers looking at the interaction between COVID and the gut microbiome. Many of these studies demonstrate the possible contribution of gut bacteria to COVID infection and severity, as well as the effect COVID (and its treatment) potentially has on our gut bacteria.

Now, a new study has found severe COVID may be related to fungal bugs in our gut microbiome. This could be through a variety of changes to the immune system in response to specific fungal species.

Also Read | Humans evolved with their microbiomes – like genes, your gut microbes pass from one generation to the next

What the study did

Fungal organisms in the microbiome are referred to as the fungal microbiota, or mycobiota. While it’s normal to have a range of fungal organisms in the gut, changes in the types or amount can be linked to disease, just like with variations in gut bacteria.

In the study published in Nature Immunology, the researchers investigated the possible relationship between mycobiota and COVID in a few different ways.

First, they compared patients with and without COVID, looking at the levels of certain fungal organisms in samples from their gastrointestinal tracts. This included 66 people with severe COVID, 25 with moderate COVID and 36 without COVID.

The researchers also measured antibodies in the participants’ blood against these same organisms, which lets us know that they triggered an immune response.

Explained | How does the gut microbiome link to autism spectrum disorders?

To investigate further, the researchers conducted experiments in mice. They gave the mice some of the fungal organisms taken from COVID patients and measured some of the same outcomes, including antibodies in the blood. They also looked to see if certain treatments, such as antifungals, would make a difference.

While this isn’t the first study looking at gut mycobiota and COVID, it’s very comprehensive and reports some interesting findings.

What the study found

The researchers detected a greater amount of fungal organisms in patients who had COVID compared with controls who did not.

Antibodies to certain fungi were also heightened in the blood of COVID patients. In other words, the presence of these fungal organisms and an associated immune response seems to be linked to a more severe COVID infection. In particular, two Candida species and S. cerevisiae were linked to disease severity.

When the researchers isolated live fungi from fecal samples of COVID patients, Candida albicans was common in the gut of patients with COVID, and its growth correlated with more severe disease.

Also Read | COVID and your gut: How a healthy microbiome can reduce the severity of infection – and vice versa

To look at the impact of these fungal species on immune responses, mice were colonised with Candida strains isolated from the COVID patients.

The researchers found older mice who were colonised with C. albicans and then infected with COVID showed a very different immune response compared to mice that weren’t given the Candida fungus. This included having more immune cells called neutrophils in the blood and increases in other markers of inflammation including in the lungs.

Some of these changes were partially resolved with anti-fungal treatment or other specific anti-inflammatory medications that have shown benefit in COVID patients.

Some limitations

All of this suggests variations in the mycobiota may contribute to the excessive inflammatory immune response seen in severe cases of COVID. A link between the fungal microbiome and inflammation isn’t completely new – other studies have shown an impact on inflammatory conditions linked to similar changes in the mycobiota.

As with all studies, there are some limitations to consider here. First, the number of human participants was relatively low, with only 91 patients with COVID included, and 36 in the control group. Many parts of the study analysed even smaller groups of patients or patient samples.

Also Read | Are you sure you contain 10x as many microbes as human cells? 

Second, the study was conducted in 2020 during the first wave of COVID infections. A lot has changed since then including the virus itself. And most people have now not only been vaccinated but also previously exposed to the virus.

Nonetheless, this study raises many possibilities including perhaps being able to look at who might be a greater risk of more severe COVID based on their mycobiota. There may even be a possibility of trying to change the mycobiota to reduce the risks from COVID infection. But to get to these points we need a lot more research.

There are multiple factors that determine the make-up of our microbiome, including mycobiota. These are likely to include diet and lifestyle factors alongside other factors like medical conditions and treatments, such as antibiotics.

At this stage there are fewer proposed interventions for influencing mycobiota than for gut bacteria. But studies such as this one demonstrating the importance of the fungal bugs in our gut will hopefully lead to more research in the area.