By Dr Chun Tang — MBChB (Manchester), MRCGP, MBA · Practising NHS & Private GP · Founder, Little Ox

Dr Tang in the Press: Is It Covid or a Cold? How to Tell This Autumn

In October 2025, I was quoted in The Portugal News and several UK publications on one of the perennial autumn questions that comes back every year as respiratory virus season begins: how do you tell whether that scratchy throat and runny nose is Covid or a common cold?

It's a genuinely confusing question now that newer Covid variants tend to cause milder, more cold-like symptoms than the original strain — and because both viruses circulate simultaneously through autumn and winter.

What I Said in the Press

Here's my breakdown of the key clinical differences:

The cause: Colds are typically caused by rhinovirus — a tough little virus that loves to colonise your upper respiratory tract. Covid is caused by SARS-CoV-2, a coronavirus that can go deeper, sometimes affecting the lungs and in some cases other organ systems.

Shared symptoms: Both can cause sore throat, runny or stuffy nose, sneezing and cough. This overlap is why distinguishing them by symptoms alone can be difficult.

Covid-specific markers: Fever (more common with Covid), significant fatigue — what patients describe as feeling like they've been "hit by a truck" — muscle aches, and the loss of taste or smell (less common with newer variants but still a marker). Covid tends to cause more systemic symptoms; a cold tends to stay in the head and chest.

Duration: Colds typically resolve in 7–10 days. Covid symptoms often persist for up to two weeks, and can trigger prolonged fatigue or other symptoms in some people.

Testing: If you're genuinely unsure and it matters — because you work with vulnerable people, or because you have underlying health conditions — lateral flow tests are still available from pharmacies and remain a useful tool.

When to see a GP: High fever that won't settle, difficulty breathing, chest pain, symptoms beyond 10–14 days without improvement, or if you feel something is significantly wrong. Trust your instincts — if you're worried, get checked.

Winter Immunity and NAD+

Respiratory virus season is the time of year when the connection between cellular immune health and how you get through winter is most practically relevant. The efficiency of your immune response to respiratory viruses — how quickly you mount a defence, how effectively you clear the infection, how well you recover — is directly tied to your cellular metabolism status.

T-cells, the immune cells that identify and destroy infected cells, require substantial NAD+ to function at full capacity. NAD+ depletion after 40 doesn't prevent your immune system from working — but it can slow its response time and reduce its efficiency, which is reflected in the clinical observation that older adults tend to have more prolonged and severe respiratory illness than younger adults even when the infection itself is identical.

Supporting NAD+ with daily NMN Pure, combined with Bio Cultures Complex for gut-immune axis support and Magnesium Glycinate for quality sleep (which is when immune consolidation happens), gives you the cellular foundation for getting through winter in better shape.

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