(CNN) — Autumn has arrived in the Northern Hemisphere, and the weather is starting to get cooler. Many people have cold-like symptoms, and some may test positive for Covid-19, influenza or respiratory syncytial virus (RSV).
As winter approaches and viral infections increase, many people may be wondering how long it takes to become contagious after getting sick and how long it takes to take precautions to avoid contact with others.
How do people know if they are still contagious? If so, what is the average time it takes for viruses like coronavirus, influenza, respiratory syncytial virus, or the common cold to spread to other people? What precautions should infected people take in schools, workplaces and at home?
To guide us through these questions, I spoke with CNN Health medical expert Dr. Leana Wen. Wen is an emergency physician and professor of health policy and management at the George Washington University Milken Institute School of Public Health. She previously served as Baltimore’s health commissioner.
CNN: Is there an easy way to tell if a person is still contagious after contracting the virus?
Dr. Wen Lina: The truth is, no. For many viruses, an infected person is contagious even before they begin to show symptoms.
Additionally, while there are tests that can show whether you have the virus, they are not typically used to discharge someone from the hospital after infection. COVID-19 is an exception. According to the Centers for Disease Control and Prevention (CDC), a person can end quarantine if their symptoms are improving and they receive negative results on two home coronavirus tests taken 48 hours apart.
Another complicating factor is that many people may continue to experience persistent symptoms long after their infectious period has ended. For example, it’s common to have a cough for weeks or even months after a respiratory illness. These symptoms indicate ongoing inflammation of the respiratory tract but do not reflect an ongoing infection or risk to others.
CNN: If a person is infected with a common virus such as coronavirus, influenza, respiratory syncytial virus or the common cold, what is the average time it takes for a person to spread the virus to others?
arts: Let’s review them one by one. The virus that causes Covid-19, known as SARS-CoV-2, can be spread by asymptomatic infections without any of the common symptoms, such as cough, fever, runny nose and sore throat. Infected people who are not yet showing symptoms (that is, people who are pre-symptomatic) may also be contagious.
Scientists estimate that the maximum infectious period of SARS-CoV-2 occurs in the 48 hours before symptoms appear and within five days after symptoms appear. The CDC recommends that people infected with Covid-19 quarantine for five days and then wear a good, well-fitting mask when in contact with people for the next five days unless they test negative twice in a row. As I mentioned before.
Asymptomatic spread of influenza may be less common. Although you may be able to spread the flu to others before you develop symptoms, the maximum period of contagion is thought to be three to four days after illness onset.
The CDC warns that healthy adults may be contagious to others for up to five to seven days after becoming ill, and some people, such as those with weakened immune systems, may be contagious for longer.
RSV infection is a very common respiratory infection that is believed to affect almost all children before the age of two. People with RSV are usually contagious three to eight days after the onset of symptoms, although pre-symptomatic transmission is also possible. According to the CDC, some infants and immunocompromised people may continue to spread the virus for up to four weeks after symptoms resolve.
As for the common cold, there are over 200 viruses that can cause it. The contagious period depends on the virus and the health of the person infected, but generally, it follows a similar pattern to the other viruses mentioned above.
In summary, a person can be contagious for a period of time before symptoms appear, and typically the most contagious period is three to five days after symptoms appear. However, they may be able to spread the virus for up to two weeks after infection.
CNN: With such a long period of potential contagion, what precautions should people with cold-like symptoms take in schools and workplaces?
arts: Schools and workplaces have long recognized that it is unrealistic to ask people to stay at home until the entire period in which they may have been contagious has passed. Even if they have policies that require people not to go to school or work until two weeks or even four weeks after symptoms disappear, the virus can still spread due to asymptomatic and pre-symptomatic transmission.
And, considering that children experience an average of six outbreaks of viral respiratory infections per year, compared with two to four for adults, such a policy would result in significant absenteeism, with numerous consequences for children’s learning and development, not to mention the sequelae. About the workplace and the economy.
Many schools have policies in place to try to balance the importance of keeping children in school with the importance of limiting their presence during peak periods of contagion. For example, they may ask parents to keep their children home if they have a fever and require that the child has been fever-free for at least 24 hours without taking fever-reducing medications before returning. Sometimes, if a child continues to have significant symptoms (such as a cough), they may need a note from their doctor.
Work centers may have these or other protocols. If you are unsure, ask Human Resources. In general, if you have a fever and start to experience new active symptoms, it’s best to stay home. If you must return to work, be sure to wear a high-quality, well-fitting mask in public or shared spaces to avoid infecting others.
CNN: What should people do to avoid infecting the people they live with?
arts: It’s very subtle. Parents of young children know that when their children get sick, they often get sick because it is difficult to avoid infection when in close contact.
The key is to identify family members who are most vulnerable to these viruses. If everyone is generally healthy, many families will decide not to take extraordinary measures to isolate people with cold-like symptoms. On the other hand, if someone is elderly and has a serious health condition, it makes sense to separate the infected person from that person. The two people should not eat together or be in the same room for at least a week after symptoms begin.
These viral infections are difficult to avoid, but I want to maintain that prevention methods can and do work. Wash your hands often or use hand sanitizer. Make sure you’re up to date on your vaccinations, including the newer Covid-19 vaccine, flu vaccine, and the new RSV vaccine for those over 60. These vaccines are critical to reducing the risk of severe disease and the chance of contracting these specific viruses.