Study suggests some drug resistance to influenza B medications

April 3, 2007

Use of certain common antiviral drugs during a recent influenza B epidemic in Japan showed the development of viruses with partial resistance to the drugs, according to a study in the April 4 issue of JAMA.

Two antiviral drugs, zanamivir and oseltamivir, which are a type of drugs known as neuraminidase inhibitors, have been effective against influenza and are used extensively. There has been documented evidence of the emergence of oseltamivir-resistant type A viruses, but similar information on influenza B viruses has been limited. Influenza B viruses are associated with annual outbreaks of illness and increased death rates worldwide, according to background information in the article.

Shuji Hatakeyama, M.D., Ph.D., of the University of Tokyo, Japan, and colleagues examined the prevalence and transmissibility of influenza B viruses with reduced sensitivity to neuraminidase inhibitors in Japan, where zanamivir and oseltamivir are now used more extensively than anywhere else in the world. In the winter of 2004-2005, an influenza B virus caused a widespread epidemic in Japan, creating an opportunity to assess the effectiveness of neuraminidase inhibitors. The researchers collected influenza B isolates from 74 children before and after oseltamivir therapy and from 348 untreated patients with influenza (including 66 adults). Four hundred twenty-two viruses from untreated patients and 74 samples from patients after oseltamivir therapy were analyzed.

The researchers identified a variant with reduced drug sensitivity in one (1.4 percent) of the 74 children who had received oseltamivir, and seven (1.7 percent) of the 422 influenza B viruses isolated from untreated patients were found to have reduced sensitivity to zanamivir, oseltamivir, or both. Review of the clinical and viral genetic information available on these seven patients indicated that four were likely infected in a community setting, while the remaining three were probably infected through contact with siblings shedding the mutant viruses.

“Continued surveillance for the emergence or spread of neuraminidase inhibitor–resistant influenza viruses is critically important,” the authors write. “Further evaluation of the biological properties of neuraminidase inhibitor–resistant influenza viruses is needed to fully assess their pathogenicity in humans.”

In an accompanying editorial, Anne Moscona, M.D., of Weill Medical College of Cornell University, New York, and Jennifer McKimm-Breschkin, Ph.D., of Molecular and Health Technologies, Parkville, South Victoria, Australia, comment on the findings concerning possible drug resistance to influenza B medications.

“The report by Hatakeyama et al raises more questions than it answers, including questions about viral evolution, biological fitness, and transmissibility. But some facts are strikingly clear. Influenza B mutants with reduced sensitivity to neuraminidase inhibitors are circulating, and these viruses can cause infections with no difference in duration of symptoms, level of viral shedding, or clinical outcome. Contrary to what had been hoped until now, some resistant variants are vigorous pathogens. Whether these viruses arise by spontaneous mutation or through drug selection, or whether they are transmitted within families or acquired from the community, the resistant variants may be here to stay. In light of the recent observation that oseltamivir may be less effective against influenza B than against influenza A, an important concern is whether suboptimal dosing for these viruses will lead to increased selection of viruses with high-level resistance.”

“Influenza viruses evolve rapidly and nimbly, which compels ongoing investigation of antiviral therapies that use alternative mechanisms of action and target different points in the viral life cycle. The emergence of drug-resistant influenza B should draw attention to the importance of continual monitoring of strains over time and to the need for frequent rethinking of policies for use of antiviral drugs. While the news about resistance is not good and certainly calls into question some of the current assumptions about drug-resistant viruses, an effective response to this news can help contend with the new challenges of influenza.”

Source: JAMA and Archives Journals

Explore further: H7N9 influenza is both lethal and transmissible in animal model for flu

Related Stories

H7N9 influenza is both lethal and transmissible in animal model for flu

October 19, 2017
In 2013, an influenza virus that had never before been detected began circulating among poultry in China. It caused several waves of human infection and in late 2016, the number of people to become sick from the H7N9 virus ...

Improved molecular tools streamline influenza testing and management

April 17, 2013
Over 40,000 people die each year in the United States from influenza-related diseases. In patients whose immune systems are compromised, antiviral therapy may be life-saving, but it needs to be initiated quickly. It is therefore ...

Continuing uncertainties surround anti-influenza drug

January 18, 2012
Incomplete availability of data has hampered a thorough assessment of the evidence for using the anti-influenza drug oseltamivir, a Cochrane Review has found. However, after piecing together information from over 16,000 pages ...

Take kids to get their flu shots early, experts say

September 2, 2013
(HealthDay)—As soon as the updated seasonal flu vaccine becomes available, parents should bring children aged 6 months and older to get vaccinated, according to an updated policy statement from the American Academy of Pediatrics ...

Alcoholics have an abnormal CD8 T cell response to the influenza virus

August 26, 2014
It is well known that chronic drinking is associated with an increased incidence and severity of respiratory infections. Previous research had demonstrated that an increase in disease severity to influenza virus (IAV) infections ...

Searchers map the global spread of drug-resistant influenza

September 14, 2011
In the new movie "Contagion," fictional health experts scramble to get ahead of a flu-like pandemic as a drug-resistant virus quickly spreads, killing millions of people within days after they contract the illness.

Recommended for you

Sensor-equipped pill raises technological, ethical questions

November 17, 2017
The first drug with a sensor embedded in a pill that alerts doctors when patients have taken their medications was approved by the Food and Drug Administration, raiding issues involving privacy, cost, and whether patients ...

New painkillers reduce overdose risk

November 16, 2017
Scientists on the Florida campus of The Scripps Research Institute (TSRI) have developed new opioid pain relievers that reduce pain on par with morphine but do not slow or stop breathing—the cause of opiate overdose.

Separating side effects could hold key for safer opioids

November 16, 2017
Opioid pain relievers can be extremely effective in relieving pain, but can carry a high risk of addiction and ultimately overdose when breathing is suppressed and stops. Scientists have discovered a way to separate these ...

US regulators approve first digital pill to track patients

November 14, 2017
U.S. regulators have approved the first drug with a sensor that alerts doctors when the medication has been taken, offering a new way of monitoring patients but also raising privacy concerns.

Introduction is different, but top medications for opioid addiction equally effective

November 14, 2017
With opioid addiction officially declared a public health emergency in the U.S., medical intervention to treat the illness is increasingly important in responding to the epidemic. Now, a new study concludes that two of the ...

Drugstore pain pills as effective as opioids in ER patients

November 7, 2017
Emergency rooms are where many patients are first introduced to powerful opioid painkillers, but what if doctors offered over-the-counter pills instead? A new study tested that approach on patients with broken bones and sprains ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.