Mysterious Fog in the US , Canada and UK: A dense, eerie fog with a "burning chemical-like smell" has spooked a good part of North America and parts of the United Kingdom and Canada. With social media amplifying all concerns, this phenomenon has sparked attention across all social media platforms. However, at the heart of this mysterious fog are a conjunction of natural events, social psychology, and environmental conditions that culminated in all the conspiracy theories and public health fears. Here's a closer look at the mysterious fog, its potential causes, and the societal response it has triggered.

Fog that Feeds Fear

The first reports of this "mysterious fog" came in from Florida where a resident said that they experienced respiratory symptoms, feverish warmth, and stomach cramps after contact with the fog. Similar stories started flooding social media, and within a day or two, a sinister force seemed to sweep across the United States, Canada, and parts of the UK. From Texas to Minnesota, people reported weird odors and health issues that they thought were linked to this bizarre atmospheric event.

Some witnesses were said to see "white particles" swirling through the air; theories ranged from a chemical attack or experimental weapon to drone-related chemical dispersals and references to historical military experiments, such as the infamous 1950s "Operation Sea-Spray."

Fuel to the fire were added when videos and posts, hundreds of thousands in number, began circulating on social media sites like TikTok and X (formerly Twitter) speculating on the origin of the fog. Hashtags like #ToxicFog went trending for days. Hysteria created a self-reinforcing loop in which every post spurred further scrutiny and fear.

Scientific Explanation of the Dense Mysterious Fog

1. What is Fog?

Fog is essentially a low-lying cloud formed when the air temperature cools to its dew point, causing water vapor to condense into tiny droplets or ice crystals. Several types of fog—advection fog, radiation fog, and valley fog—can form depending on conditions such as warm, moist air moving over cooler land or when temperatures plummet rapidly under clear skies.

2. Why the Chemical Smell?

Such chemical-like smell as reported during the occurrence of fog events is sometimes attributed to air pollution. It acts like a sponge, where it absorbs these pollutants, which include sulfur dioxide and nitrogen oxides, among others, that emit from industries. This mixture, therefore, leads to a stench that could be mistaken as unnatural or even toxic.

Also Read: Health Concerns Rise As US, Canada, and UK Come Under The Blanket Of Thick, Dense, Toxic Fog

3. What are the Health Concerns?

High moisture levels from fog can significantly exacerbate symptoms related to respiration, but especially in already predisposed asthmatics and allergy patients. The connection of these symptoms with actual fever, stomach cramps, and puffy eyes is too remote. Experts assume that the irritating effects of entrapped pollutants trapped in fog tend to affect more the eyes and throat rather than the rest of the body affected by some report.

Psychological Effects of Mass Panic Caused by Social Media

Social media amplified a natural weather event into a health epidemic. It made the personal experience of individuals become a cause for fear and speculation, a domino effect.

According to psychologists, this is a concept of selective perception, wherein once people's attention is drawn to environmental anomalies, they begin to notice them. This mirrors earlier panics, such as the Seattle windshield pitting panic of 1954. Then, atomic bomb testing caused fear in many and started to have people looking at their windshields for small marks that they had not seen before. Likewise, postings on the strangeness of the fog probably increased public awareness and suspicion, with people looking to attach unrelated symptoms to the phenomenon.

The fog hysteria shares a commonality with other instances of mass panic, such as the "drone sightings" of recent years or the Cold War-era fears of biological warfare.

Also Read: Mysterious Fog Is Making Americans Sick

These events underscore how fear can cloud judgment, especially when amplified by social media and sensationalist headlines. While historical cases, such as "Operation Sea-Spray," offer concrete evidence of the existence of unethical experiments, the jump from a natural weather condition to theories of chemical attacks exemplifies a more modern trend of connecting unrelated dots, all wonderfully seeded in distrust and anxiety.

Despite the swirling rumors, meteorologists and scientists are in agreement that the mysterious fog is not as alarming as it seems. It is well known that fog traps and amplifies pollutants, especially in urban and industrial regions. Moreover, winter months are the most conducive for fog formation, so its recent prevalence is unsurprising.

On the other hand, environmentalists advise that the fog should wake everyone up to increased levels of pollution. The reported odors and health irritations could be just symptoms of far deeper systemic issues like industrial emissions and lack of control over air quality.

The authorities must be transparent in their communication to combat misinformation and allay public fears. Governments and environmental agencies must provide timely updates on weather phenomena, air quality, and health risks. Initiatives like real-time pollutant tracking and public education campaigns can help demystify natural occurrences while addressing valid environmental concerns.

The mysterious Canada fog is a compelling case study in how environmental events intersect with psychology and societal dynamics. While rooted in natural phenomena, the fog became a vessel for collective fears, amplified by modern technology and historical anxieties.

In this information era where communication occurs at an almost lightning pace, the fog becomes a metaphor that reminds everyone about scientific literacy, environmental responsibility, and an effective balance when considering public concern. Whether perceived as a marvel of nature or as a tale that serves to teach, it left a very powerful mark in people's minds.

Centres for Disease Control and Prevention (CDC) has issued an advisory urging American travellers over the age of 60 years to avoid the Chikungunya vaccine, Valneva's 'Ixchiq'. Health authorities had earlier asked the elderly to take these shots in the wake of Chikungunya outbreaks in the islands of the Indian Ocean. However, last week, they stated 17 serious adverse events, including two deaths, which were reported in recipients of the vaccine IXCHIQ over the age of 60 worldwide, and asked the elderly to refrain from using the vaccines.

"CDC and FDA recently investigated five hospitalisations for cardiac or neurologic events following vaccination with IXCHIQ among older people. We are also aware of additional reports of serious adverse events among people aged 62 to 89 years following the use of IXCHIQ in other countries. CDC and FDA advise the live-attenuated vaccine should not be used among people 60 years and older until these additional reports are further investigated," the CDC mentioned on their website.

Chikungunya Surge In Indian Ocean Islands

France's Departments of La Reunion and Mayotte have reported chikungunya outbreaks. La Reunion has reported over 47,000 cases and 12 associated deaths as of May 4 this year. Meanwhile, the World Health Organisation (WHO) has warned that the cases are expected to rise in the region. In the wake of the same, health authorities have asked travellers and pregnant women to avoid or reconsider travelling to those regions.

What Is Chikungunya?

Chikungunya is a mosquito-borne viral disease caused by the chikungunya virus. Symptoms of the disease include fever and joint pain. The risk of a person spreading the virus is highest during the first week of illness. The European Union's health regulator is currently reviewing Valneva's chikungunya vaccine after reports of serious adverse events, including two deaths globally. The European Medicines Agency's safety committee has temporarily suspended the use of the vaccine-Ixchiq, in adults aged 65 years and above.

Chikungunya Vaccine Under Investigation

Ixchiq is the first preventive vaccine against the chikungunya virus authorised in Europe and the US. While the adverse effects of this jab is still not fully revealed, the deaths of two adults aged 62 and 89 years have raised alarm. However, the exact link between the vaccine and the death is being determined by the health officials. At present, the French government has suspended the use of the vaccine pending investigation after adverse events were reported as well. Meanwhile, the US advisors have recommended the second chikungunya vaccine, Bavarian Nordic's Vimkunya, to those above 12 years of age.

The government of the United States has now advised its travelers who are of 60 years and above to not get a chikungunya vaccine. This has come at the backdrop of the investigation of the vaccine, which may have possible side effects.

As of late last week, the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) posted notices about the same. It recommended the pause in use of Ixchiq, the Chikungunya Vaccine, Live.

The notice read:

As of May 7, 2025, 17 serious adverse events, including two that resulted in death, have been reported in individuals 62 through 89 years of age who received Ixchiq during postmarketing use globally. Six of these reports have been from the United States (U.S.). Most U.S. and foreign serious adverse events that have been reported to the Vaccine Adverse Event Reporting System (VAERS), co-managed by FDA and CDC, have been in individuals with underlying chronic medical conditions. Adverse events reported to VAERS may not be causally related to vaccination. Approximately 80,000 doses of Ixchiq have been distributed globally.

It was last year when the government had recommended the vaccine which is made with weakened chikungunya virus. The vaccine was recommended to all US adults who travel to countries where chikungunya could be an issue.

However, it was last month when a panel of vaccine experts who advice CDC heard about an investigation into 6 people who are 65 and older, most with pre-existing medical conditions, who became ill with heart or brain symptoms in less than a week after being vaccinated. More than 10 other such cases have been reported in people from other countries too.

What Happens From A Chikungunya Vaccine?

Chikungunya vaccine is alive injection that is used to prevent infection caused by the chikungunya virus. The vaccine works by causing your body to produce antibodies against the disease.

Why people with pre-existing medical condition may undergo other health symptoms after the vaccine is administered? There may be due to drug interaction. Anyone with pre-existing health condition may already be prescribed certain medications, which may interact with the ones injected from the vaccine.

The vaccine is also capable of causing severe or prolonged chikungunya-like reaction as it consists the weakened virus of the same diseases.

What Are The Common Side Effects Of The Vaccine?

There are certain side effects of the vaccine which may happen to anyone who has taken it, they include:

• Difficulty in moving
• Fever
• Joint Pain
• Muscle pain or stiffness

Some of the side effects which are not that common include:

• Bloating or swelling of the face, arms, hands, lower legs, or feet
• Burning, numbness, tingling, or painful sensations
• Rapid weight gain
• Tingling of the hands or feet
• Unsteadiness or awkwardness
• Unusual weight gain or loss
• Weakness in the arms, legs, or feet

There are other side effects too, which are often not intensely known, they include:

• Blurred vision
• Coma
• Confusion
• Decreased urine output
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• fainting
• fast or irregular heartbeat
• headache
• increased thirst
• muscle cramps
• seizures
• sweating
• swelling of the face, ankles, or hands
• swollen joints
• trouble breathing
• unusual tiredness or weakness

While some side effects may occur, they usually do not need medical attention. However, if you are on any other medication, a strong drug, then you may need to be put under supervision to see how the drug reacts with your body's immune system.

As medicinal science progresses, researchers have developed an AI mechanism that uses a selfie to determine a patient's biological age and judge how well they may respond to cancer treatment. The research, which was published in the journal Lancet Digital Health and stated that because humans age at different rates, their physical appearance may offer insights into their so-called "biological age". This biological or physiological age can help estimate a cancer patient's response to chemotherapy.

How Was FaceAge AI Tool Developed?

The researchers wanted to analyse whether a person's biological age could be tested based on how a person looks. This could include whether someone could undergo intensive cancer treatment based on how frail they appear to be. Researchers said they wanted to see whether they could go beyond the subjective and manual eyeball test by creating a "deep learning" artificial intelligence, or AI, tool which could assess simple selfies. That is how they created the FaceAge AI tool. Trained using 59,000 photos, this AI tool can estimate a person's biological age, as opposed to their actual age, by scanning an image of their face.

"Our study now has shown for the first time that we can really use AI to turn a selfie into a real biomarker source of ageing," said Dr Hugo Aerts, corresponding author of the paper.

Researchers found that the biological age of patients with cancer was, on average, five years higher than their chronological age. They also found that older FaceAge AI readings were associated with worse survival outcomes, especially in people over 85 years of age.

More studies assessing FaceAge are underway, including whether it could be used for other conditions or diseases and what impact things like cosmetic surgery or Botox have on the tool’s accuracy.

"We have demonstrated that AI can turn a simple face photo into an objective measure of biological age that clinicians can use to personalise care for patients, like having another vital sign data point. It was another piece of the puzzle, like vital signs, lab results or medical imaging. We want to be clear that we view AI tools like FaceAge as assistance, [to] provide decision support and not replacements for clinician judgment," Dr Ray Mak, co-senior author of the paper, said.