The influenza A H3N2 virus of season 2017-2018 has claimed many lives, including children, in the United States. But just as people thought that it was over, another influenza type is beginning to whip up the second wave of illnesses in the country. And the culprit is the influenza B virus which was confirmed by the Centers for Disease Control and Prevention.

Influenza B: How Dangerous Can It Be

Influenza virus B is a kind of influenza that has a limited number of hosts, compared to influenza virus A. Aside from infecting humans, influenza B can also infect harbor seals or Phoca vitulina, according to a 2000 study by researchers from The Netherlands. The recent report from the CDC confirmed the increasing number of affected individuals in the US.

"While H3N2 viruses remain predominant overall this season, during week 12, influenza B viruses were more frequently reported than influenza A viruses," CDC stated in their report.

When it comes to pandemics, influenza A is well-known to deliver widespread global health crisis in many parts of the globe, such as:

- The Spanish Flu in 1918 that involved the H1N1 virus strain, which killed up to 100 million people.

- The Swine Flu in 2009 that involved the H1N1 strain as well, which killed more than 14,000 people.

- The Russian Flu from 1889 t0 1890 that killed about 1 million people. Experts have been investigating the flu strain that caused this pandemic. Early investigations suggested that the pandemic was caused by H2N2 strain, while later assertion determined H3N8 strain. The H2N2 strain is believed to exist among birds, while the H3N8 strain is endemic among birds, horses, and dogs.

- The Hong Kong Flu in 1968 that involved the H3N2 strain, which killed about one million people.

Aside from pandemics, the influenza A also caused several epidemics in different territories including the Fujian flu in China and the Central Luzon flu in the Philippines. The virus was also involved in several outbreaks in Croatia, India, and the UK.

Even though influenza A is a lot more dangerous than influenza B, the public should remain vigilant because flu viruses are unpredictable. Flu viruses, including A and B, are capable of mutation every now and then that makes the development of the vaccine very difficult. These pathogenic viruses can mutate in two ways – antigenic drift and antigenic shift. In antigenic drift, the proteins in the surfaces of flu viruses change over time that can still be recognized by the immune system, while in an antigenic shift, the proteins suddenly change that the makes it difficult for the immune system to fight off.

"We don't want to say, 'Oh, it's only influenza B, you don't need to worry.' We don't want to put out a false sense that it's any less severe. Unfortunately, there will still be pediatric deaths this flu season, but there's no need to panic. Influenza B tends to not be as contagious from person to person, so it's slightly easier to prevent," explained Stephen Ferrara, an expert in flu viruses and an associate dean of clinical affairs at Colombia University School of Nursing.

To prove that influenza B can a serious threat to human health, the CDC revealed some details in the March 24 report:

- One death has been confirmed that occurred on February 10, 2018.

- About 2,066 cases were confirmed positive in the lab test for influenza B in the week ending on March 24.

- About 696 cases of influenza B were confirmed with antiviral resistance since October 1, 2017.

"The dominant strains every year are one of the A strains. They create the big epidemics. Now, behind the scenes as it were there are influenza B strains that are circulating at the same time," stated Dr. William Schaffner, an infectious disease expert at Vanderbilt University.

Influenza B: How to Protect Yourself and Your Family

Scientists do not know why influenza B does not cause epidemics and prefers to be opportunistic. Still, the influenza B infections can still lead to untimely death, particularly in people with compromised or weakened immune systems. Here are some ways to prevent you or your family from contracting the virus, according to the CDC:

1. Get a flu shot: While the vaccine cannot provide 100 percent protection against the virus, it can help reduce the duration of the symptoms. It also helps individuals who have a weaker immune system, such as people with HIV, cancer patients, and younger children.

2. Do not spread the germs: Proper handwashing is the most effective way to avoid spreading the virus. You can use soap and water to wash your hands properly or use an alcohol-based hand rub, such as a sanitizer.

3. Antivirals: If you contracted the virus, do not ignore the doctor's prescription of antivirals. These drugs are designed to reduce the symptoms and speed up your recovery.

[메디컬리포트=Ralph Chen 기자]