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COVID-19, smell and taste – how is COVID-19 different from other respiratory diseases?

COVID-19, smell and taste – how is COVID-19 different from other respiratory diseases?



A health worker carries out an olfactory test to monitor smell loss to a resident 65 km from Buenos Aires city, on May 24, 2020, amid the COVID-19 coronavirus pandemic. ALEJANDRO PAGNI/AFP via Getty Images

In March 2020, Google searches for phrases like “can’t taste food” or “why can’t I smell” spiked around the world, particularly in areas where COVID-19 hit hardest. Still, many of us have experienced a temporary change in the flavor of our food with a common cold or the flu (influenza). So, is COVID-19 – the disease caused by the SARS-CoV-2 virus – somehow special in the way it affects smell and taste?

We are researchers who study the relationships between human behavior and the sensations people experience from chemicals in daily life. Upon learning that COVID-19 might differentially affect taste and smell, we thought our expertise might be relevant, so we got to work.

The flavor of food is more than just taste

When people “taste” food, they are experiencing input from three different sensory systems that are knitted together to form a singular unified sensation. Strictly speaking, taste describes the five qualities we sense on the tongue, including sweet, salty, bitter, sour and savory/umami. Savory, also known as umami, refers to the meatiness of broth, cheese, fish sauce, or a sundried tomato.

Taste involves more sensory systems than just your mouth. Tom Merton / Getty Images

Other sensations from food occur via our sense of smell, even though we experience them in the mouth. Volatile chemicals are released when we chew. These chemicals travel through the back of the throat to reach smell receptors found at the top of the nasal cavity, right behind the point where your eyeglasses rest on your nose.

The third sensory system involved in food flavor involves touch and temperature nerves that can also be activated by chemicals. This is known as chemesthesis. In the mouth, these sensations include the burn of chili peppers, the cooling of mouthwash or mints, the tingle of carbonation, or the vibrating buzz of Sichuan peppers. Together, these three chemosensory systems – taste, smell and chemesthesis – work to define our perceptual experiences from food.

Common viral infections attack the nose more than the mouth

Loss of smell is common with many viruses, including rhinoviruses, influenza, parainfluenza and coronaviruses, and it is normally attributed to nasal inflammation that restricts airflow.

If your nose is blocked, it is not surprising you are not able to smell much. Typically, the other two systems – taste and oral chemesthesis – are not affected, as a blocked nose does not alter our ability to taste sugar as sweet or feel the burn from a chili pepper. With time, most patients recover their senses of smell, but occasionally some do not. Causes vary, but in some individuals, inflammation from a viral illness appears to permanently damage key structures located around the smell receptors.

SARS-CoV-2 isn’t like those other viruses

Since early spring 2020, firsthand reports have indicated that the SARS-CoV-2 virus, the novel coronavirus that causes COVID-19, might affect the mouth and nose more severely than the common cold or the flu. Not only were the reports of loss more frequent, but they also differed from what is normally seen.

One British surgeon with COVID-19 posted a video to Twitter showing that he had lost the ability to feel the burn of chilies. Others, like Penn State undergraduate Caela Camazine, reported losing their sense of smell and taste completely without any nasal congestion.

Dr. Whitehead has lost his ability to taste the burn of chili peppers. Screen grab

Based on the spike in Google searches, and these atypical accounts of chemosensory loss, more than 600 researchers, clinicians and patient advocates from 60 countries formed the Global Consortium for Chemosensory Research.

The Global Consortium for Chemosensory Research launched a global survey in 32 different languages to better understand what COVID-19 patients are experiencing. Initial results from our survey support the idea that COVID-19 related losses are not limited to smell, as many patients also report disruption of taste and chemesthesis.

Our understanding of how the SARS-CoV-2 virus can affect multiple sensory systems is still quite limited, but is advancing daily. Initial work suggests that smell disturbances in COVID-19 patients are caused by the disruption of cells that support olfactory neurons. In our noses, we have nerve cells called olfactory sensory neurons, which are covered with odor receptors tuned for certain volatile chemicals. When a chemical binds an odor receptor, the olfactory sensory neuron fires a signal to the brain which we perceive as a smell. Notably, it does not appear that the virus targets olfactory sensory neurons directly.

Instead, the virus seems to target specialized supporting cells that cradle the olfactory sensory neurons. These support cells are covered with a different receptor, the ACE2 receptor, which acts as an entry point for the virus. In contrast, the way SARS-CoV-2 might directly affect taste and chemesthesis remains unknown.

Will COVID-19 patients recover their sensory perception?

We just don’t know yet whether COVID-19 patients will recover their sense of smell, taste and chemesthesis. Many patients have reported recovering completely within two or three weeks, while others report their sensory loss lasts for many weeks. To connect with other individuals who are experiencing smell and taste loss related to COVID-19, consider reaching out to organizations advocating on behalf of those who suffer from smell and taste loss, such as AbScent and FifthSense.

Because more data are needed, we are asking for your help in our research. If you know anyone who is (or recently has been) coughing and sniffling, invite them to complete the Global Consortium for Chemosensory Research survey, which takes about 10 minutes.

We want anyone who has had any upper respiratory illness (COVID-19 or not) recently so we can compare individuals with COVID-19 to individuals with the flu or the common cold. By volunteering for our study, or by spreading the word on this research study, you can contribute to better understand how COVID-19 is special in its ability to affect smell, taste and chemesthesis.

[Get facts about coronavirus and the latest research. Sign up for The Conversation’s newsletter.]

John E Hayes has received research funding from federal agencies (USDA, NIH), state agencies (PA Dept of Ag), and commodity groups (PA Wine Marketing Research Board, The Sugar Association). He has accepted travel expenses and speaking fees from non-profit organizations (ILSI North America), and food companies (Kerry Group, Hershey Company). He has consulted for the federal government (FDA) and food companies (Heineken, General Mills, PepsiCo) on flavor perception. He serves as a Section Editor for the journal Physiology & Behavior. His laboratory at Penn State, the Sensory Evaluation Center, also conducts routine taste tests for industrial clients to provide experiential learning for graduate and undergraduate students.

Valentina Parma is a scientific consultant for CyNexo (

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Bitcoin price must break $31K to avoid 2023 ‘bearish fractal’

BTC price needs to recoup some more key levels before ditching longer-term bearish risk, the latest Bitcoin analysis says.



BTC price needs to recoup some more key levels before ditching longer-term bearish risk, the latest Bitcoin analysis says.

Bitcoin (BTC) held above $30,000 at the Oct. 23 Wall Street open as analysis said BTC price strength could cancel its “bearish fractal.”

BTC/USD 1-hour chart. Source: TradingView

BTC price preserves majority of early upside

Data from Cointelegraph Markets Pro and TradingView followed BTC/USD as it hovered near $30,700, still up 2.5% on Oct. 23.

The largest cryptocurrency made snap gains after the Oct. 22 weekly close, stopping just shy of $31,000 in what became its highest levels since July. 

Now, popular trader and analyst Rekt Capital is keen to see the $31,000 level break. 

“Bitcoin has Weekly Closed above the Lower High resistance to confirm the breakout,” he commented alongside the weekly chart.

BTC/USD annotated chart. Source: Rekt Capital/X

Rekt Capital argued that BTC/USD could disregard the bearish chart fractal in play throughout 2023 next. This had involved the two year-to-date highs near $32,000 forming a doubletop formation, with downside due as a result.

Specifically, Bitcoin requires a “breach” of $31,000 in order to do so. 

More encouraging cues came from the True Market Deviation indicator from on-chain analytics firm Glassnode.

As noted by its lead analyst, Checkmate, on Oct. 23, the metric, also known as the Average Active Investor (AVIV) profit ratio, has crossed a key level.

Bitcoin’s True Mean Market price (TMM) — the level that BTC/USD spends exactly 50% above or below — is now below its spot price, at $29,780. 

“Have we now paid our bear market dues?” Checkmate queried, describing TMM as Bitcoin’s “most accurate cost basis model.”

Bitcoin True Market Deviation (AVIV) chart. Source: Checkmate/X

Institutions awaken in “Uptober"

Analyzing the potential drivers of the rally, meanwhile, James Van Straten, research and data analyst at crypto insights firm CryptoSlate, flagged the potential approval of the United States’ first Bitcoin spot-price-based exchange-traded fund (ETF).

Related: BTC price nears 2023 highs — 5 things to know in Bitcoin this week

While not yet awarded the green light, a U.S. spot ETF is being treated as an inevitability after legal battles resulted in regulators losing sway.

“The potential approval of a spot ETF for Bitcoin has spurred a significant increase in bullish inflows in the crypto market,” Van Straten wrote in an update published on Oct. 23.

He noted that Glassnode data shows inflows via over-the-counter (OTC) trading desks spiking since late September.

“In addition, the Purpose Bitcoin ETF, with its holdings of approximately 25,000 Bitcoin, has observed consistent inflow throughout the past month. Even though these inflows might not be termed as ‘large,’ they denote a positive market sentiment,” he continued.

“This uptick in inflows across various platforms indicates an optimistic market response to the potential approval of a Bitcoin ETF, bolstering the overall landscape of digital assets.”
Bitcoin transfers to OTC desk wallets. Source: CryptoSlate/Glassnode

The largest Bitcoin institutional investment vehicle, the Grayscale Bitcoin Trust (GBTC), continues to see a lower discount to the Bitcoin spot price, having already seen its smallest negative margin since December 2021.

This stood at -13.12% as of Oct. 23, per data from monitoring resource CoinGlass.

GBTC premium vs. asset holdings vs. BTC/USD chart (screenshot). Source: CoinGlass

This article does not contain investment advice or recommendations. Every investment and trading move involves risk, and readers should conduct their own research when making a decision.

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California bill aims to cap crypto ATM withdrawals at $1K per day to combat scams

A new legislative investigation found some crypto ATMs charging a premium as high as 33%, while a few ATMs had limits of up to $50,000.



A new legislative investigation found some crypto ATMs charging a premium as high as 33%, while a few ATMs had limits of up to $50,000. California legislators have proposed a new bill titled “Digital financial asset transaction kiosks,” calling for a cap on crypto ATM withdrawals of $1,000 per day in light of growing scams. Additionally, starting in 2025, the law would limit operators’ fees to $5 or 15% (whichever is higher). The bill, if approved, would come into effect on Jan. 1, 2024. The bill was introduced after legislative members visited a crypto ATM in Sacramento and found markups as high as 33% on some crypto assets compared with their prices on crypto exchanges. On average, a crypto ATM charges fees between 12% and 25%, according to a legislative analysis. Government officials also found ATMs with limits as high as $50,000, prompting them to take regulatory measures to curb such high premiums and withdrawal limits. There are more than 3,200 Bitcoin ATMs in California, according to Coin ATM Radar. Democratic State Senator Monique Limón, who co-authored the proposed legislation, said the “new bill is about ensuring that people who have been frauded in our communities don’t continue to watch our state step aside” when there are real issues happening. Another provision of the bill would require digital financial asset businesses to obtain a license from the California Department of Financial Protection and Innovation by July 2025 Crypto ATMs are a popular way for people to exchange cash for their choice of cryptocurrency but have become a hub for scams and exploits because of the nature of transactions (i.e., hard cash). Unlike bank and wire transfers, each transaction leaves less of a trail. Related: CoinSmart president says crypto taxes are a ‘little bit more favorable’ outside US Some residents have recently been caught up in such scams, where the scammer persuades the victim to go to a nearby crypto ATM and deposit cash for the crypto of their choice. Some of those affected by ATM scams have lauded the bill and said the low transaction limit would give victims time to realize if they are being duped, reported the LA Times. On the other hand, crypto ATM businesses said the new bill would harm the small operators who must pay rent on their ATMs. The operators noted that the bill fails to address the core issue of the fraud and instead takes a punitive path focused on a specific technology. They warned such a move would shudder the industry and hurt consumers while doing nothing to stop bad actors. Magazine: Bitcoin is on a collision course with ‘Net Zero’ promises

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Fighting the Surveillance State Begins with the Individual

It’s a well-known fact at this point that in the United States and most of the so-called free countries that there is a robust surveillance state in…



It’s a well-known fact at this point that in the United States and most of the so-called free countries that there is a robust surveillance state in place, collecting data on the entire populace. This has been proven beyond a shadow of a doubt by people like Edward Snowden, a National Security Agency (NSA) whistleblower who exposed that the NSA was conducting mass surveillance on US citizens and the world as a whole. The NSA used applications like those from Prism Systems to piggyback on corporations and the data collection their users had agreed to in the terms of service. Google would scan all emails sent to a Gmail address to use for personalized advertising. The government then went to these companies and demanded the data, and this is what makes the surveillance state so interesting. Neo-Marxists like Shoshana Zuboff have dubbed this “surveillance capitalism.” In China, the mass surveillance is conducted at a loss. Setting up closed-circuit television cameras and hiring government workers to be a mandatory editorial staff for blogs and social media can get quite expensive. But if you parasitically leech off a profitable business practice it means that the surveillance state will turn a profit, which is a great asset and an even greater weakness for the system. You see, when that is what your surveillance state is predicated on you’ve effectively given your subjects an opt-out button. They stop using services that spy on them. There is software and online services that are called “open source,” which refers to software whose code is publicly available and can be viewed by anyone so that you can see exactly what that software does. The opposite of this, and what you’re likely already familiar with, is proprietary software. Open-source software generally markets itself as privacy respecting and doesn’t participate in data collection. Services like that can really undo the tricky situation we’ve found ourselves in. It’s a simple fact of life that when the government is given a power—whether that be to regulate, surveil, tax, or plunder—it is nigh impossible to wrestle it away from the state outside somehow disposing of the state entirely. This is why the issue of undoing mass surveillance is of the utmost importance. If the government has the power to spy on its populace, it will. There are people, like the creators of The Social Dilemma, who think that the solution to these privacy invasions isn’t less government but more government, arguing that data collection should be taxed to dissuade the practice or that regulation needs to be put into place to actively prevent abuses. This is silly to anyone who understands the effect regulations have and how the internet really works. You see, data collection is necessary. You can’t have email without some elements of data collection because it’s simply how the protocol functions. The issue is how that data is stored and used. A tax on data collection itself will simply become another cost of doing business. A large company like Google can afford to pay a tax. But a company like Proton Mail, a smaller, more privacy-respecting business, likely couldn’t. Proton Mail’s business model is based on paid subscriptions. If there were additional taxes imposed on them, it’s possible that they would not be able to afford the cost and would be forced out of the market. To reiterate, if one really cares about the destruction of the surveillance state, the first step is to personally make changes to how you interact with online services and to whom you choose to give your data.

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