When the novel coronavirus arrived in the United States at the beginning of the year, little was known about it other than its symptoms: fever, cough, and shortness of breath.

But as the virus continues to spread, public health officials are compiling more information about it, including additional symptoms, how it is spread, and how people can protect themselves and others from contracting the coronavirus.

Here are answers to some frequently asked questions as knowledge about the coronavirus and how to treat it evolves.

What additional symptoms are people with COVID-19 reporting?

The Centers for Disease Control and Prevention (CDC) has added new symptoms to its official list of COVID-19 symptoms since the first case was diagnosed in the U.S. in January, based on the observations of doctors treating thousands of patients during the pandemic.

As of May, the CDC officially listed these symptoms: chills, muscle pain, headache, sore throat, new loss of taste or smell, congestion or runny nose, nausea or vomiting, and diarrhea. Those are in addition to previously known symptoms of fever, cough, and shortness of breath or difficulty breathing.

Because new information about the disease is becoming available all the time, the CDC and other health experts are constantly revising their data, leading the agency to provide the following disclaimer on its symptoms page: “This list does not include all possible symptoms. CDC will continue to update this list as we learn more about COVID-19.”

Can people who have the virus spread it even if they don’t have symptoms?

Some people who contract the coronavirus don’t show symptoms. But those infected people could pass it on to others who would get sick, according to the CDC. These asymptomatic carriers make up 35 percent of all coronavirus infections. 

The most recent information from the World Health Organization (WHO) is that while asymptomatic transmission does occur, no one knows for sure how frequently it happens.

How does blood type influence the coronavirus? 

Some people who contract the coronavirus might not even notice they have been infected, while others who develop COVID-19 need medical treatment, hospitalization, and in the most severe cases, the use of a ventilator. 

New research published in the peer-reviewed New England Journal of Medicine by a team of European scientists suggests that a person’s blood type could play a role in the severity of COVID-19 symptoms. People with Type A blood and COVID-19 are 50 percent more likely to experience respiratory failure, the research found.

Meanwhile, COVID-19 patients with Type O blood have a 50 percent reduced risk of severe infection compared to patients with COVID-19 who have other blood types.

Researchers examined more than 1,600 coronavirus patients undergoing treatment for severe coronavirus at seven medical centers in Italy and Spain. They found that a region of the participants’ genomes that helps code for blood type was linked to a patient’s chances of developing severe symptoms.

While the sample size was small, the research aligns with findings from two similar studies done in the U.S. and China that were not peer-reviewed. In New York, researchers analyzed 1,559 COVID-19 patients in April and found a higher proportion of infected patients had blood type A and a lower proportion had type O. 

In March, a study of more than 2,173 coronavirus patients from three hospitals in China found that patients with blood type A were at a higher risk of getting sick from coronavirus infections compared to people with other blood types. The researchers also observed that people with blood type O had a lower risk for infection.

What is the risk of catching coronavirus from touching something? 

Becoming infected with the novel coronavirus after touching a contaminated object is not typically how the novel coronavirus spreads, but it can happen, according to the CDC. 

The primary way the virus spreads is through close contact from person to person by breathing in droplets containing the virus. It’s possible for someone to become infected after touching a surface or object that has droplets containing the coronavirus on it and then touching the mouth, nose, or possibly eyes. 

By following social distancing and local public health guidelines, such as staying at home when you can, wearing a face mask when you must go out, and washing your hands regularly, you help to lower your risk of infection.

Is it safe to exercise while wearing a mask?

commentary published this month on the website of the British Journal of Sports Medicine points out that using a face mask during exercise “comes with issues of potential breathing restriction and discomfort” and requires “balancing benefits versus possible adverse events.”

If you don a mask before running or cycling at your usual pace, your heart rate will be more elevated than before, according to Cedric Bryant, president and chief science officer of the American Council on Exercise, a nonprofit organization that funds exercise research and certifies fitness professionals.

Bryant said whether working out at the gym or outdoors, people should anticipate a heart rate about eight to 10 beats higher per minute when wearing a mask during exercise, and the rise in heart rate will be most pronounced during intense workouts.

The WHO does not recommend that people wear face coverings while exercising, and instead recommends people exercise only when able to practice physical distancing.

 An executive order issued on June 17 by Bexar County Judge Nelson Wolff mandates face coverings for the general public and directs all commercial entities, including gyms and fitness studios, to require employees and patrons to wear them in situations where social distancing is not feasible.

Does wearing a mask cause you to breathe in unsafe levels of CO2?

Too much CO2, or carbon dioxide, can be life-threatening, but only at significantly high concentrations, experts say.  Most people wear face coverings for short periods of time, so it is unlikely that wearing a face covering will cause people to breathe in enough CO2 to cause excessive carbon dioxide in the bloodstream.

Some people with preexisting respiratory conditions, including asthma or cystic fibrosis, may be at risk with prolonged use of tight-fitting masks, like N95 respirators.

Can flushing a toilet spread coronavirus?

A recent study published by Physics of Fluids, a monthly peer-reviewed scientific journal covering fluid dynamics, showed via computer model that when someone defecates and flushes the toilet, the turbulent activity associated with flushing can send tiny droplets 3 feet or more above the bowl, where they can be inhaled or fall onto bathroom surfaces. 

While there is some evidence that the coronavirus can survive as it passes through the digestive tract and into feces, neither the WHO nor the CDC think it’s very likely COVID-19 can be spread by bowel movements leading to accidental consumption of virus particles, a route medically termed fecal-oral transmission.

But study authors say the possibility of that mode of transmission calls for action in the midst of a pandemic. They recommend closing the toilet lid while flushing if possible, and when using a toilet without a lid, such as those in public restrooms, use a face mask and be sure to not touch your face before washing your hands.  

There have been no reports of fecal-oral transmission of COVID-19 to date, according to the WHO. 

Is there evidence that antibodies are beneficial?

Several studies have now shown that most people who develop COVID-19 also develop antibodies to the coronavirus, although it has been unclear how long those antibodies provide protection against contracting it again.

A new study published in the peer-reviewed journal Nature Medicine suggests the protective proteins made in response to infection may last only two to three months, especially if the person showed no symptoms to begin with. Authors caution against the idea of “immunity certificates” for people who have recovered from the illness. 

While antibodies can prevent the virus from entering into a human cell and causing an infection, not every antibody is equally protective.

With businesses now required to mandate face coverings, where can you report violations in Bexar County?

Under the order, all commercial entities in Bexar County are required to implement a health and safety policy that includes mandatory face coverings in situations involving close contact with others. An individual can’t be fined for failure to wear a mask, but businesses can be fined up to $1,000 for failing to implement face-covering policies.

Residents can call 3-1-1 of the San Antonio Police Department non-emergency line at 210-207-SAPD (7273) to report violations. 

Roseanna Garza

Roseanna Garza

Roseanna Garza reports on health and bioscience for the San Antonio Report.