Your body is like Fight Club. When an unwanted infection attempts to seize control, it sparks a body-wide brawl - fever vs. germs. The ring announcer? Your brain, sending chemical signals to your core to crank up the heat. Coupled with chills, these mechanisms are your body's roundhouse kicks against microscopic invaders.

But what's the deal with body aches and chills where a fever fails to show up, like it stood us up? Enter the COVID-19 virus and infections like bacterial meningitis. They're working behind the scenes, tampering with the hypothalamus - your body's temperature regulator. Like a Bond villain, they lower your core body temperature in stealthy subterfuge.

Where does that leave you, then? Betwixt a bout of the chills and languishing under the weight of your duvet. But woe betide rushing for a pill just yet. A fever isn't officially so until your body temperature scales over 100.3 degrees Fahrenheit (F). Anything underneath that, and it's just the common cold bluffing you.

For the germaphobes among us, here's how the whole thing goes down: Pyrogens - foreign substances that trigger a fever - take charge when germs like viruses or toxins produced by bacteria pay your body an uninvited visit. These pyrogens summon inflammatory warriors known as prostaglandins from the battleground site of the infection, which then "convince" the hypothalamus (your temperature thermostat) to turn up the heat.

But it doesn’t stop at infections. Certain medications can also stir a fever in people with hypersensitivity to the drug, causing their immune system to rally its defenses.

As for infections that cause body aches and chills sans fever, they include COVID-19 and certain bacterial infections. While the fever is a frequent guest of COVID-19, some people have reported feeling chills without fever. It's like a party where the main DJ never showed up, but everyone's still trying to get their groove on.

When it comes to bacterial infections instigating chills without fever, these bacteria are like duplicitous agents. Rather than stimulating the release of prostaglandins independently, like viruses, they produce toxins that are pyrogenic, duping the body into believing it’s in a feverish state.

Now, if you're shaking like a leaf in a winter storm while suffering an infection, the urge to burrow under a heap of blankets is understandable. But beware, as it would only catapult your body temperature upwards, cause more discomfort, and even pave the path towards dehydration.

Remember, fever and chills are merely your body's brawny bouncers, determined to keep ill-intentioned germs out. Reaching out to a healthcare provider for treatment isn't necessary unless your fever spikes above 102 degrees F or you spot some serious signs and symptoms.

Until then, stay hydrated, rest up, and let over-the-counter medications help bring your fever down. And remember – fever isn’t the real enemy, it’s the germs that started it all.