Coronavirus is new, but don’t forget: ‘This is a very severe influenza season’

Ana Farfan reacted to getting an influenza vaccine shot at Eastfield College in Mesquite, Texas.LM Otero/Associated Press

Even as people fret about the new coronavirus, another more familiar viral infection is raging throughout Massachusetts: influenza.

The two infections seem to share similar modes of transmission and similar symptoms. But each stirs worry for different reasons.

The US Centers for Disease Control and Prevention estimates that so far this season 19 million people fell ill with the flu, 180,000 were hospitalized, and 10,000 died in the United States alone.

In contrast, so far the new coronavirus has caused more than 23,000 illnesses and nearly 500 deaths worldwide.

But the coronavirus is new, it’s spreading quickly, and its future path is unknown. Many specialists believe it will inevitably travel worldwide.

Here’s some information to help you sort this out.

Is this a bad year for the seasonal flu?

The number of medical visits for influenza-like illnesses in Massachusetts in the last week of January was higher than during that time in the previous two years, and remains high in every region of the state, as well as most of the country. A Massachusetts teenager has already died of the flu this season, one of 68 children nationwide.

“This is a very severe influenza season,” said Dr. David Yassa, chief of clinical infectious disease and travel medicine at Atrius Health, a large organization of Eastern Massachusetts medical practices. “We’re seeing a lot of patients coming in and calling in with influenza-like illness.”

At the same time, the state is reporting fewer influenza hospitalizations than in the past few years, a sign that this year’s strains of flu are causing milder illness. And some doctors are not seeing a huge influx of cases.

Dr. David Gilchrist, a family medicine doctor with Reliant Medical Group in Worcester, said half as many Reliant patients had been hospitalized in January of this year compared with last year, though both illnesses and hospitalizations have been accelerating.

Still, it may be too early to characterize this year’s flu season. It’s just getting started: Flu typically peaks in February and March.

Does the new coronavirus resemble the flu?

Make no mistake, they are different viruses. But both affect the lower respiratory system, cause fever and cough, and appear to be transmitted the same way — through droplets released when a sick person breathes, coughs, or sneezes.

These similarities have prompted some people to call or visit their doctors when they get flu-like symptoms, worried it might be coronavirus. “Flu is prevalent in our communities,” said Dr. Mark Gendreau, chief medical officer at Beverly Hospital. “People are getting the flu and then they are panicking, ‘Could this be coronavirus?’ ”

But if you haven’t been to Hubei Province, China, or spent time with someone who was sick with coronavirus, you’re not at risk of catching it.

A UMass Boston student who had traveled into the heart of the epidemic in China caught the virus and came back to Boston. Couldn’t he have spread it to fellow airline passengers or others he met here?

He could have, but so far there’s no evidence he did, and he was quickly isolated as soon as he reported his illness.

Even with a strong cough, the respiratory droplets thought to carry the coronavirus can’t travel more than 6 feet, and then they drop to a surface. It’s not known how long the virus survives on a surface.

The US Centers for Disease Control and Prevention identified everyone who was seated within a few rows of the student on his flight to Boston, and notified the home states of those people. The public health agencies in each state then contacted those passengers so they could watch for symptoms, according to Massachusetts health officials.

After he got off the plane, the young man had contact with very few people, according to health officials. All those people have been notified and are being monitored.

Why haven’t health officials told the public every place the man went after he got off the plane, as they do with measles cases? Could he have infected someone on public transit or in an Uber?

Measles is highly contagious. The virus travels far on the air and lingers for hours. You could walk into a room where someone with measles had stood hours earlier and catch the virus (if you haven’t been vaccinated). That’s why efforts are made to let the public know every place a measles patient has visited.

Coronavirus is different. It floats on heavy respiratory droplets that travel no more than 6 feet and then fall. Health officials did not detail the man’s itinerary, but they did say they were able to reach all his close contacts — defined as anyone who was within 6 feet of him for at least 10 minutes. One could conclude from this information that he was unlikely to have taken public transit, and if he took an Uber, the driver has probably been notified.

Can coronavirus be transmitted by people without symptoms?

Chinese officials have reported anecdotally that they believe it can. But the one seemingly well-documented report of such asymptomatic transmission in Germany turned out to be false. Health authorities believe that while asymptomatic transmission may occur, the disease’s spread is driven primarily by people who are coughing and sneezing.

Is the coronavirus something to worry about?

Yes. Any emerging infection is cause for concern, because there are so many unknowns. The health news site STAT interviewed specialists who foresaw two possible scenarios. The new coronavirus may join the four other coronaviruses that are always circulating, causing mostly mild illnesses like the common cold. Or, it may act like the flu, cycling back to attack on a seasonal basis. Notably, they didn’t predict that the virus would be contained or eliminated.

So far, the new coronavirus appears not to cause severe illness. Only two deaths have been reported outside of China. This is cold comfort, however, to anyone who is highly vulnerable to respiratory infections, such as the elderly or people with chronic lung disease or weakened immune systems.

Several companies are working on a coronavirus vaccine. But even if a vaccine candidate can be developed quickly, it will still require many months of testing to make sure it is safe and effective. It’s unlikely a vaccine could be ready for market in less than a year.

At this point — with only 12 cases reported in the United States so far, travelers from Hubei Province, China, being quarantined, and doctors everywhere watchful — health officials say the risk remains extremely low that individuals in the United States will catch coronavirus.

“People are much more at risk of getting the flu,” Gilchrist said. “We need to stay focused on that.”