Diana Zuckerman, Ph.D., Thomas Eagen, Ph.D., Meg Seymour, Ph.D., Sophia Phillips, M.S., Avni Patel, Angelica Estrada
Updated October 18, 2022
The coronavirus can infect anyone, young or old, healthy or frail. Here’s what you need to know.
What is coronavirus?
Coronaviruses are a large group of viruses that can cause respiratory illness. The new (novel) coronavirus is called SARS-CoV-2 and the illness it causes is called coronavirus disease 2019, which is why it’s abbreviated as COVID-19. This virus is highly contagious and deadly with over 200 million confirmed cases and over 4.5 million deaths globally. As of September 19, 2022, there have been 95 million confirmed cases in the U.S. and over 1 million deaths.
Who is at risk of severe illness from COVID-19?
Older adults or people who have cancer and other serious health conditions are at increased risk for getting seriously ill from COVID-19. These individuals and their loved ones need to be especially careful to avoid getting infected and potentially hospitalized. The Centers for Disease Control and Prevention (CDC) has a list of health problems that put people at greatest risk of severe illness from COVID-19, which include underlying medical conditions such as: chronic kidney disease, chronic obstructive pulmonary disease (COPD), obesity (body mass index of 30 or higher), weakened immune system (from cancer or an organ transplant), serious heart conditions, sickle cell disease, and Type 2 diabetes. This risk has been shown to increase with age. Smoking also increases the risk of being seriously harmed by the virus.
A study published in the Journal of the American Heart Association in 2021 found that two-thirds of COVID-19 hospitalizations can be attributed to four cardiometabolic conditions: obesity, high blood pressure, diabetes, and heart failure. Many other medical conditions might contribute to an increased risk of severe illness, including asthma, developmental disabilities, high blood pressure, neurologic conditions (e.g., dementia), cerebrovascular disease (e.g., stroke), and pregnancy. A study published in the Journal of the American Medical Association (JAMA) Oncology in December 2020 of more than 6 million cancer patients, found that people diagnosed with cancer during the previous year are much more likely to die of COVID-19 compared to other COVID-19 patients. Several studies suggest that all cancer patients are at higher risk of dying, but the ones in most danger had been diagnosed with leukemia, non-Hodgkin’s lymphoma, or lung cancer. However, COVID patients who had been recently treated with chemotherapy were not more likely to die of COVID and COVID patients who had recently been treated with immunotherapy were less likely to die of COVID.
The virus usually spreads through close contact with other people, especially through invisible or very tiny droplets when a person coughs, sneezes, sings, exercises – or even when they breathe or talk normally. These droplets can travel through the air and can be inhaled or get into the noses, mouths, or eyes of people nearby. That’s why good protective masks are so important. For example, a study published in 2022 of people who had recently been exposed to someone with a COVID infection found that the person’s risk of developing a COVID infection was cut in half if both people wore masks. Although masks are rarely required in 2022, many individuals at higher risk due to their age or medical issues continue to benefit from wearing masks. The virus is thought to be most contagious in the days just before and just after a person develops symptoms, but it is possible to catch the virus from infected people who have no symptoms at all. Becoming infected by exposure to people with no symptoms may be especially likely.
Unlike the flu, which is riskiest for the youngest children and oldest adults, infants and young children are much less likely to get seriously ill from the coronavirus than adults. Early in the pandemic, there were few known examples of the virus spreading in daycare centers that follow coronavirus safety standards. Nevertheless, by September 8, 2022, 14.6 million children had been diagnosed with the virus in the U.S. Fortunately, few children become so sick that they are hospitalized or die.
How does COVID-19 spread between people?
The virus usually spreads through close contact with other people, especially through invisible or very tiny droplets when a person coughs, sneezes, sings, exercises – or even when they breathe or talk normally. These droplets can travel through the air and can be inhaled or get into the noses, mouths, or eyes of people nearby.
The virus is thought to be most contagious in the days just before and just after a person develops symptoms, but it is possible to catch the virus from infected people who have no symptoms at all. Becoming infected by exposure to people with no symptoms may be especially likely with the Delta variant, or if the asymptomatic person was vaccinated.
Do we know how the virus is changing?
It is normal for viruses in the environment to change or mutate, resulting in new variants of the same virus. This is why the CDC recommends that adults and children receive a seasonal flu shot – to strengthen the body’s immune response against the variant with the potential to spread throughout a community. Many variants of the COVID-19 virus have emerged globally during the pandemic. The U.S. government is routinely monitoring for variants of concern that may show:
- Evidence of impact on diagnostics, treatments, or vaccines
- Evidence of increased transmissibility
- Evidence of increased disease severity
The Delta variant, was a dominant variant which was first identified in December 2020 in India. It was followed by the Omicron variant that was first identified in November 2021. This variant was shown to be more transmissible and more resistant to vaccines than other variants. By March 2022, a variant of Omicron, known as BA.2, had resulted in an increase in cases in Europe and had spread to the U.S. as well. The BA.5 variant soon followed in August, 2022. As of October 12, 2022, BA.5 accounts for 88% of cases in the U.S. and is the most contagious strain so far. Even if you have been infected with other strains, including previous Omicron strains, you can still get infected with BA.5. However, preliminary research suggests it is less likely to cause severe illness compared to other variants, and is more likely to cause upper respiratory symptoms such as sore throat, persistent cough, and runny nose. Of concern in late October 2022, is a new variant known as BQ.1 which is gaining momentum in the U.S. It is predicted to be the leading variant in the upcoming months.
View our other articles on how to prevent COVID-19, and what to do if you have symptoms.
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