If you want to stay healthy despite the illnesses spreading through our community, it’s important to keep on top of the latest medical news. That’s why we are launching the Cedars-Sinai Health Forecast, which tracks the most widespread illnesses and zeroes in on how to identify them and what to do if you or a loved one gets sick.

Check out what our experts are saying.

Feeling under the weather or downright sick? These illnesses—with very similar symptoms—are the most likely culprits:

Influenza
Respiratory syncytial virus (RSV)
COVID-19

How do I know which one I have? If you feel sick, get tested. It’s the only way to know for sure. Testing especially helps those at risk of complications or more severe illness.
Self-care: Supportive care—the catchphrase physicians often use to refer to care provided at home—includes fluids, rest and over-the-counter medications to treat symptoms. Humidifiers can help with congestion, especially in babies and older kids. Nasal suction is important, too, for congested babies.
How to prevent: Good hand-washing habits and covering coughs and sneezes can help you avoid getting sick. Vaccinations can prevent or significantly lessen the severity of these illnesses. In 2024, new vaccines for RSV became available.
When to see a doctor: Difficulty breathing and pain or pressure in the chest or abdomen may signal the need for immediate medical attention. If rest and supportive care don’t lead to improvement or symptoms worsen, consult your doctor.
Expert take: “Influenza is a fairly tough illness, but this year that’s especially true,” said Sam Torbati, MD, co-chair of the Department of Emergency Medicine at Cedars-Sinai. "When people get sick, they feel horrible."
Handy household tool: Oximeters—devices either clipped on your finger or installed in your smartwatch to measure oxygen in your blood—became popular during the peak of the COVID-19 pandemic. “That’s a useful tool to assess your need to get seen by a doctor,” said James Rhee, MD, an emergency medicine physician at Cedars-Sinai Marina del Rey Hospital. “If your oxygen saturations are low, you need to go to an emergency department for evaluation.” Readings below 92% are cause for concern.

Other respiratory infections
Plenty of other illnesses commonly cause colds and ailments but usually don’t lead to testing since they don’t have specific treatments. Their symptoms and care mirror those for flu, RSV and COVID-19.

Read: Ask a Doc: What’s Walking Pneumonia?

Norovirus
Norovirus is often called, and not affectionately, “the winter vomiting bug,” for reasons obvious to anyone struck with it. It’s the nation’s leading cause of vomiting, diarrhea and foodborne illness. While not as prevalent as flu or RSV, the illness spiked in recent months, especially in December.
Common symptoms: Nausea, vomiting, diarrhea, stomach pain, fever and muscle pain. Symptoms usually emerge 12 to 48 hours after exposure and last one to three days.
Self-care: Drink fluids, including rehydration and sports drinks without caffeine. Rest and eat bland foods. In short, prevent dehydration!
How to prevent: Proper handwashing helps. Stick to soap and hot water. Alcohol-based hand sanitizer doesn’t work on this virus.
When to see a doctor: Diarrhea that doesn’t go away in three days, signs of dehydration, severe vomiting or bloody stools all warrant getting medical care. Children who cry but have few or no tears may be dehydrated. 

Pertussis
Pertussis, a highly contagious bacterial infection also known as whooping cough, is on the rise in California, with more than 2,000 cases reported in 2024. It’s most dangerous for babies, who often require hospitalization if they catch it.
Common symptoms: Severe cough, sometimes followed by a “whooping” sound after taking a breath. Begins with mild symptoms, including nasal congestion, watery eyes, fever and cough. After a week or two, the coughing attacks worsen and can cause vomiting, extreme fatigue, and redness or blueness in the face. Babies may not cough, but struggle to breathe.
How to prevent: Vaccinations are the best protection. Full vaccinations or periodic boosters are recommended for everyone from 2-month-old infants to people over 65 years old. Find detailed vaccine criteria at the Centers for Disease Control and Prevention (CDC) website.  
When to see a doctor: Any pertussis symptoms, especially the “whoop,” should prompt a doctor’s visit. Turning red or blue, struggling to breathe, vomiting, and an uncontrollable fever require emergency medical attention.

Pneumonia
Doctors are seeing some spikes in pneumonia, especially those caused by the bacteria mycoplasma pneumoniae, said Nathanial Spencer, MD, an emergency medicine specialist at Cedars-Sinai Marina del Rey Hospital.
Common symptoms: Cough, sore throat, headache, congestion, low-grade fever, fatigue and sneezing. Symptoms can appear gradually and last for weeks or, for coughs, even months.
Self-care: Use rest, fluids and medications to soothe symptoms.
How to prevent: Good hand hygiene helps. Vaccines are recommended for children under 5 and adults over age 65. Any adult with a lung condition or other medical risk factor should consider vaccination.
When to see a doctor: If you’re treating your symptoms with supportive care and you’re not getting better, schedule a visit with your doctor.

Read: Flu and RSV: How to Protect Yourself Now

Avian Flu
Jonathan Grein, MD, director of hospital epidemiology and infection control officer for Cedars-Sinai, noted that the H5 virus—colloquially called avian flu—is making headlines. “We have yet to see person-to-person transmission, and we really hope it stays that way,” he said. Those who work directly with wild birds, poultry, cattle and dairy operations are at highest risk. In addition to specific guidance for those working in jobs where they may come in contact with sick animals, the CDC advises avoiding exposure to wild birds and avoiding raw milk and raw milk products.

Fires and Public Health
The devastating toll of the wildfires in the Los Angeles area continues to stress communities and our personal health. Learn more at the Cedars-Sinai Newsroom.

Prepare for Summer
Summertime infections are often tough to predict. In recent years, international travel—and travel-related illness—have spiked. Consider an appointment with a travel clinic if you are heading abroad.