Fall and winter mark the peak season for common respiratory infections such as respiratory syncytial virus, or RSV; influenza; and the common cold. These illnesses — along with COVID-19, which tends to peak at similar times — often begin with similar symptoms, so telling them apart can be tricky, especially when the beginning of cold and flu season can be the tail end of seasonal allergies.
Ann Sheehan, assistant dean for faculty practice and associate professor at MSU’s College of Nursing, has been a pediatric nurse practitioner for more than 20 years. She currently helps families at MSU Health Care Pediatrics make informed decisions about children’s health
Here, Sheehan provides insights about how to determine a child’s sickness, why it’s important to differentiate the illnesses, and what can speed recovery.
Some symptoms of common illnesses look the same. How can parents tell them apart?
Figuring out whether your child has COVID-19, the flu, RSV or the common cold is important because some of these illnesses can cause serious complications in certain children.
COVID-19 has a higher risk of severe or long-term health effects, including long COVID, but others are not harmless. The flu can cause significant illness and hospitalization, and RSV can be especially serious for infants, young children and those with chronic health conditions.
All four of these illnesses spread easily. Keeping children home when they are sick helps reduce that spread, protecting vulnerable classmates and school staff.
Colds are caused by a variety of viruses, which is why they are so common. Frequent cold symptoms include coughing, sneezing, sore throat and a runny nose. These symptoms are generally mild and usually improve on their own within about seven to 10 days.
COVID-19, on the other hand, is caused by a single virus called severe acute respiratory syndrome coronavirus 2, or SARS-CoV-2.
The symptoms of COVID-19 tend to last longer — seven to 14 days, with some lingering for three to four weeks. Beyond common cold symptoms like a cough, sore throat and runny nose, people sick with COVID-19 often have body aches, shortness of breath and difficulty breathing, headache, fatigue, fever and loss of taste and/or smell.
Signs that often differentiate COVID-19 are stomach symptoms such as abdominal pain, vomiting and diarrhea. Not all children experience these symptoms, but they are not associated with the common cold.
The symptoms of the flu, caused by the influenza A or B virus, tend to come on very quickly, unlike the gradual onset of a cold or COVID-19. Symptoms last about three to seven days, and they’re very similar to those of COVID-19, except they don’t usually include loss of taste or smell.
RSV symptoms also align with those of a cold but include a decreased appetite. Also, RSV affects the lungs and can lead to serious lung infections and hospitalization, especially for infants and toddlers. The symptoms can last three to four weeks.
When should parents keep their kids at home from school?
If your child has symptoms that could be one of these viruses, keeping them home from school is a good idea. It helps protect other children and school staff from becoming ill.
A general rule of thumb for making the call is to consider whether your child can comfortably participate in classroom activities. If the answer is yes, then it’s likely fine to send them to school. But if they’ve had a fever in the past 24 hours, or have diarrhea, nausea or vomiting, it’s best that they stay home and rest.
The American Academy of Pediatrics notes that children with certain medical conditions, including obesity and diabetes, immune system deficiencies and complex medical conditions, may be more likely to become seriously ill if they contract COVID-19, RSV or the flu.
Are COVID-19 tests helpful for diagnosing illness at home?
It’s often impossible to tell if a child has COVID-19 based on symptoms alone. A home COVID-19 test can be a useful tool if, for example, your child has some of the typical symptoms or was exposed to someone with COVID-19 — or if your child has a chronic medical condition that puts them at high risk of complications.
A positive result is reliable, but a negative result does not completely rule out a COVID-19 infection. That could be because you made an error in following the testing instructions or because there’s not enough virus present to turn the test positive.
If the test is negative and symptoms remain, the Centers for Disease Control and Prevention recommends retesting in 48 hours or having your healthcare provider order a PCR test.
What vaccines are recommended for children?
The American Academy of Pediatrics recommends flu vaccinations for all children over the age of 6 months, unless a child has a medical reason not to receive it. The group recommends that children ages 6 to 23 months old, and children ages 2 to 18 who have a higher risk of severe illness from COVID-19, get a COVID-19 vaccine. A study published in December 2025 supports this recommendation.
The American Academy of Pediatrics and the CDC also recommend that infants be immunized against RSV based on certain criteria.
It’s important to know that children can still become infected with the viruses that cause these illnesses after getting these shots. However, once a child is vaccinated against flu or COVID-19, their immune system recognizes the virus and responds more effectively. And the antibodies used to immunize infants against RSV directly protect them from illness.
Not only do these interventions reduce your child’s risk of getting severely ill and being hospitalized if they get one of these viruses, but they also reduce the number of school days your child is likely to miss.
When should a parent involve a healthcare professional?
Whichever respiratory infection your child has, unless they are at high risk for serious complications, symptoms can usually be managed at home. For most children, there’s no need to seek medical care for every cough and runny nose, even if their COVID-19 test is positive. Most children recover from these viruses without complications.
However, some symptoms may indicate a more serious illness and should not be ignored. You know your child best; if their fever does not come down with medication, they are having trouble eating and drinking, or if they are having difficulty breathing, seek medical care. Additionally, caregivers with children who have underlying medical conditions or other risk factors should contact their healthcare provider when children first experience symptoms so they can get treatment if needed.
Responses are excerpts from an article originally published in The Conversation.
