Viruses are tiny germs. They’re way smaller than bacteria: thousands can fit inside a single human cell and there may be trillions in your body when you’re ill. Many are harmless, but some can cause deadly diseases like polio and measles. Respiratory viruses prefer to infect the cells of the nose, throat, and lungs where they cause damage and stimulate the body to make mucus in an attempt to get rid of them. In fact, most of your cold symptoms are a result of your immune system trying to clear the infection. There are thousands of different viruses that can cause the common cold. Viruses are very good at mutating – they can quickly make changes to their structure that help them evade our immune system – which is why you can catch several colds per season and why you need a new flu vaccine every year.
Common cold: Over 200 different viruses have been found to cause colds. The most common is rhinovirus, but other causes include adenovirus and coronavirus (both old-school coronavirus and the newer novel coronavirus sars-cov-2 that causes COVID-19). Symptoms of a cold include feeling tired or achy, a runny-stuffy nose, sore throat, cough, and sometimes a low-grade fever (under 102). Mucus (snot) is usually thin and clear, but can be yellow or neon green. Adenovirus can also cause pink eye. Symptoms usually last from 3 to 10 days.
Flu: Flu is caused by the influenza virus. There are several types of influenza virus, but the A and B strains cause most cases. Several strains can circulate at a time which is why you can get flu more than once in a season. Symptoms include body aches, fatigue, headache, sore throat, cough, runny-stuffy nose, and fever. Some people will have vomiting, but influenza is not the same thing as the “stomach flu”. The fever associated with flu tends to be higher than what is seen with colds and may rise to 104+ in some cases. Many people have mild symptoms and get over the flu in about 5-7 days, but others can have serious symptoms and may need to be admitted to the hospital. Complications of the flu include ear infections, pneumonia, and severe asthma attacks. On average, over thirty thousand deaths are attributed to influenza each year in the U.S. alone according to CDC data.
RSV: Respiratory Syncytial Virus (just call it RSV, no one wants to try to pronounce that!) starts with the typical cold symptoms of runny nose and cough. It may or may not cause fever. In high-risk people, like young infants and the elderly, it can progress to bronchiolitis (infection in the smaller airways of the lungs) with more serious symptoms including wheezing and difficulty breathing. Premature infants are at particularly high risk for hospital admission due to bronchiolitis.
COVID 19: As many of us have discovered, the symptoms of COVID-19 can vary widely from person to person. Many may be completely asymptomatic, while others will develop respiratory failure requiring ICU-level care. The most common symptoms include fever, body aches, cough, congestion, headache, diarrhea, and chest pain or shortness of breath. Most people recover completely while as many as 25% may go on to develop “post-COVID-19 syndrome” which can include symptoms like fatigue, shortness of breath, difficulty concentrating, chronic pain, and heart or kidney damage. The fatality rate from COVID-19 has dropped significantly since the vaccine was developed.
Croup: Croup is not caused by a specific virus, but can be caused by any of the viruses already discussed. Croup occurs when the top portions of the airway (the trachea and larynx) become inflamed causing the characteristic “seal bark” cough and stridor – a high-pitched noise made during the in-breath. It is most common in infants and toddlers and tends to start suddenly in the middle of the night when the child wakes with a coughing fit. Most children have mild cases and do not need to see the doctor, but some may develop difficulty breathing and will need medical attention.
How to prevent viral respiratory infections
Because viruses are so small, they can float in the air in microscopic droplets that are released when we cough or sneeze. Fun fact: sneezes can travel up to 25 feet at a speed of over 30 miles per hour! Most of the droplets will settle within a 6-foot radius though, giving rise to the “6 feet apart” rule for social distancing. Covering your mouth and nose with a tissue, your elbow, or a mask will prevent virus-laden droplets from spreading. Good handwashing is another crucial step in preventing the spread of colds and flu. If you are sick, stay home and rest to help prevent exposing others to your germs. Safe and effective vaccines are available to prevent influenza and COVID-19. These vaccines reduce the risks of severe illness, secondary complications, hospitalization, and death. While there is not currently an actual vaccine available to prevent RSV, there is a new shot containing a monoclonal antibody that helps prevent RSV infection in high-risk populations including infants and the elderly.
Treatment
The treatment of viral respiratory infections is mostly geared toward relieving symptoms. Fever reducing medication, humidifiers, and age-appropriate over-the-counter cough and cold medications may help reduce discomfort. It is always important to drink plenty of water to stay extra hydrated. When we have fever, cough, or diarrhea, we lose more fluids than usual and there is a risk of dehydration. Boosting fluid intake also helps keep mucus thinner so it is easier to clear. When symptoms are more severe, your doctor may prescribe things like anti-nausea medication, inhalers for asthma, or steroids for croup. Antibiotics are medications that treat bacterial infections. They will not make a viral infection better and should be avoided. That being said, sometimes a viral infection can set us up for bacterial infections like ear infections, sinusitis, or pneumonia. Your doctor can determine if these secondary infections are present and treat you appropriately. There are anti-viral medications available that help with flu and COVID-19 infections, but not for other respiratory viruses. These usually work by stopping the virus from making copies of itself and need to be started within a few days of symptom onset to be effective.
When to seek medical care
If you or your child develop difficulty breathing, confusion, neck stiffness, or signs of dehydration, call 911 or seek medical attention immediately in the nearest emergency room. Dehydration may be present when the inside of the mouth is dry, tears aren’t made during crying, or urine output is decreased and the color is dark yellow. Newborns and young infants should be seen in the office or ER for any fever over 100.4°F (38°C), poor feeding, or if they either cry inconsolably or are difficult to wake up. Older infants and children should be seen in the clinic for higher fever, decreased fluid intake, worsening cough, or ear pain. It is always a good idea to call your doctor if you’re concerned that you or your child are sicker than usual.
Bonus Vegetable Soup Recipe
We all know how comforting a hot bowl of soup can be when we’re under the weather. As a bonus, I’m sharing a link to my all-time favorite recipe for the best vegetable soup you will ever have. It’s called ‘Seriously Good Vegetable Soup’ for a reason! Packed with tons of healthy veggie goodness and a spectacular flavor profile, I’m certain that you will want to make this soup every time the outside temperature drops or your body-temperature rises!