Evidence-Based Medical Knowledge You Can Trust
Infectious diseases are illnesses caused by bacteria, viruses, fungi, or parasites, spreading through contact, food, water, or vectors.
Last Updated: September 18, 2026 | Medically Reviewed Sources: FDA, CDC, Cleveland Clinic, Johns Hopkins, Cochrane Database Quick Answer: If you have COVID symptoms and your rapid test is negative, retest in 48 hours. A single negative test does NOT rule out COVID-19. If you’re high-risk, contact your doctor immediately don’t wait for a positive … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD. Quick Summary: 1. Medical Overview and Pathophysiology Measles, scientifically known as rubeola, is one of the most infectious viral diseases known to medical science. It is caused by an enveloped, single-stranded, negative-sense RNA virus belonging to the Morbillivirus genus within the Paramyxoviridae family. Humans are … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD Key Takeaways 1. Medical Overview and Pathophysiology Questions regarding whether COVID is on the rise again reflect observable clinical and epidemiological shifts. Surveillance data from the CDC and World Health Organization (WHO) demonstrate recurring waves of SARS-CoV-2 transmission, primarily driven by immune-evasive subvariants such as … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD. Quick Summary EMERGENCY WARNING: Paxlovid is an outpatient treatment for mild-to-moderate COVID-19 and is not a substitute for emergency room care or oxygen therapy. Call 911 or seek immediate emergency medical care if you or someone in your care experiences: Medical Overview and Pathophysiology Paxlovid … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD Quick Answer EMERGENCY WARNING: Seek immediate emergency medical attention (call 911 or visit the nearest emergency department) if you or someone under your care experiences severe trouble breathing, persistent pain or pressure in the chest, new confusion, inability to wake or stay awake, or pale, … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD. Quick Summary: EMERGENCY WARNING: If your dog displays blue, purple, or pale gums, rapid or severely labored breathing, extreme collapse, high fever exceeding 104°F (40°C), coughing up bright red blood, or complete inability to keep fluids down, seek immediate emergency veterinary medical care. These red-flag … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD. Quick Answer: EMERGENCY WARNING: If you or someone in your care experiences severe difficulty breathing, persistent pain or pressure in the chest, sudden confusion, inability to wake or stay awake, or a pale, gray, or blue discoloration on the lips, skin, or nail beds, seek … Read more
If you’ve recently tested positive for COVID-19, you may be wondering: can your furry best friend catch it too? The short answer is yes—but the good news is that the risk is low, and serious illness in dogs is extremely rare. Here’s what every pet owner needs to know about COVID-19 transmission between humans and dogs, … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD. Quick Answer: EMERGENCY WARNING: If you or someone in your care experiences sudden chest pain or tightness, severe shortness of breath, pain spreading to the arm, shoulder, neck, jaw, or back, unexplained sweating, dizziness, sudden confusion, or blue/gray discoloration of the lips or face, call … Read more
Quick Summary EMERGENCY WARNING: If you or someone you are caring for experiences persistent chest pain or squeezing pressure, severe or sudden shortness of breath, sudden weakness or numbness on one side of the face or body, fainting or sudden loss of consciousness, or a pale, gray, or blue discoloration of the lips, face, or … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD. Quick Summary: EMERGENCY WARNING: If you experience severe chest pain, shortness of breath, a rapid or fluttering heartbeat, severe swelling of the lips, tongue, or throat, or sudden dizziness within hours to days of vaccination, seek immediate emergency medical care (call 911 in the U.S.). … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD. Quick summary: EMERGENCY WARNING: If you or someone in your care experiences sudden, severe neurological changes—such as one-sided facial drooping, sudden weakness or numbness in an arm or leg, slurred speech or difficulty understanding language, sudden severe confusion, loss of balance, or sudden loss of … Read more
Zero-calorie sugar substitutes have long been marketed as healthy alternatives to refined sugar. Found in everything from sugar-free chewing gum and toothpaste to low-calorie jams, ice creams, and yogurts, xylitol is standard across modern diet pantries. However, major new clinical research raises critical questions about its long-term cardiovascular safety. The largest observational study of its … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD. Quick Summary EMERGENCY WARNING: High-dose intake of concentrated sugar substitutes can sometimes mask, trigger, or coincide with life-threatening cardiovascular or neurological emergencies. Seek immediate emergency services care if you or someone you look after experiences sudden, heavy pressure or a crushing sensation in the chest, … Read more
Medically Reviewed and Compiled by Dr. Adam N. Khan, MD. Quick Takeaways EMERGENCY WARNING: Seek immediate emergency care (call 911 in the U.S. or go to the nearest emergency room) if a person with suspected or confirmed measles develops severe shortness of breath, rapid or labored breathing, persistent chest pain or pressure, extreme lethargy, confusion, inability … Read more