Check out our overview of the causes, symptoms, duration, contagiousness, and treatment for 8 common illnesses
Staying informed about common infections is key to keeping ourselves and our community healthy. It can be tough to keep track of the details, so we’ve put together a table on eight common infections to help you understand and manage these conditions better. As always, check with your primary care provider if you’re unsure about any symptoms you’re experiencing, and if you should seek care.
| Cold | Cause: Various viruses, often rhinoviruses Symptoms: Sore throat, cough, runny nose, congestion, headache, fatigue. Fever, muscle aches, and lower respiratory symptoms like shortness of breath can indicate more severe infections. Duration: Symptoms peak around day 2-3, with recovery starting thereafter. Contagiousness: Most contagious during the second and third days of symptoms. Reduced contagiousness after day three or four. Treatments: No specific antiviral treatments. Over-the-counter medicines can alleviate symptoms. Home remedies can also help. |
| Conjunctivitis (pink eye) | Cause: Bacteria or viruses (commonly adenoviruses) Symptoms: Itchy, red, and weepy eyes. The virus can spread from one eye to the other, making the illness last longer. Duration: 2-7 days depending on if it spreads to the other eye. Contagiousness: Highly contagious as long as symptoms are present. Bacterial form often affects one eye while viral can affect both eyes. Treatments: A doctor should determine cause. If bacterial, they can prescribe antibiotic ointment or drops. If viral, a damp compress can help with symptoms. |
| COVID-19 | Cause: SARS-CoV-2 coronavirus Symptoms: Sore throat, congestion, fatigue, fever, cough, shortness of breath, headache, loss of taste or smell. Symptoms can be mild or severe, and some cases can develop into long COVID. Duration: Most people recover within a week, but it can be longer for some. Contagiousness: Contagious for at least first 5 days. Isolate for 5 days and wear a mask in public for next 5 days. Severe cases may require longer isolation. Treatments: Early treatment with Paxlovid antiviral within the first five days. Vaccines available for prevention. Over-the-counter cold medicines for symptom relief. Seek medical care if increasingly short of breath or confused. For best prevention get current COVID-19 vaccination. |
| Flu | Cause: Influenza A and B viruses Symptoms: Sore throat, runny nose, congestion, cough, fatigue, fever, headache, muscle aches. Possible vomiting or diarrhea. Duration: Most people feel their worst for 3 days before symptoms begin to improve. Usually lasts about a week, but can go longer. Contagiousness: Contagious for around 5 days, peaking during the first three days of symptoms. If your symptoms last longer than 5 days, you should wear a mask around others. Treatment: A doctor can prescribe antiviral treatments like Tamiflu if taken within 48 hours of first symptoms. Over-the-counter meds and home remedies for symptom relief. For best prevention get annual flu vaccination. |
| Hand, foot, and mouth disease | Cause: Enterovirus family Symptoms: Most common in children. Rash on hands and feet, mouth sores (often on gums or tongue), fever. Symptoms are worst in the first 2-3 days. Duration: Symptoms usually resolve after about a week. Contagiousness: Highly contagious when symptoms first appear. Once the fever has been gone for 24 hours, contagiousness decreases. Treatment: No specific cure. Fever reducers, painkillers like acetaminophen or ibuprofen. Cold, soft foods for mouth sore relief. |
| Norovirus | Cause: Norovirus Symptoms: Quick onset of diarrhea, vomiting, nausea, stomach pain. Duration: Symptoms usually last between 1-2 days. Contagiousness: You can still be highly contagious for weeks after symptoms end, though peak contagiousness is first few days. Important to wash hands after using bathroom and use cleaners with bleach for sanitizing. Treatment: No specific treatment. Main goal is to prevent dehydration with electrolyte-rich drinks like Gatorade or Pedialyte. |
| RSV | Cause: Respiratory syncytial virus Symptoms: Runny or stuffy nose, cough, headache, fever. More severe symptoms include wheezing and shortness of breath. Duration: Symptoms typically last around a week, though cough can linger. Contagiousness: Most contagious during the first few days. Contagiousness generally reduces around day five. Treatment: No antiviral treatments. Over-the-counter medications for symptom relief. Vaccines available for older adults and pregnant women. New treatment available for infants. |
| Strep throat | Cause: Group A streptococcus Symptoms: Intense sore throat, white film in the back of the throat, potential fever. Duration: Rapid improvement with appropriate antibiotics. Contagiousness: Once antibiotics are started, contagiousness ends within about 24 hours. Treatment: Doctor can test with a throat swab. Treated with antibiotics. Prompt treatment can prevent complications to heart and kidneys. |
