Scientists have developed a new drug that will be more effective in combating drug-resistant strains of the flu virus.

A team of international researchers have found that the newly-developed drug prevents the spread of the flu virus from one cell to the next. In a bid to spread in the body, the flu virus uses a protein, called hemagglutinin, which helps it to attach to a specific type of sugar on the surface of a healthy cell.

After the flu virus inserts its RNA (ribonucleic acid) and makes an exact copy of it inside the cell, the virus starts reproducing. It uses neuraminidase enzyme to break ties and move on to the next healthy cell, according to the researchers.

The research team studied the virus' resistance to the existing flu drugs such as Relenza and Tamiflu, so as to develop the new drug that combats the drug-resistant viruses, according to a report in The Age.

The new drug developed by scientists follows the same method as the current flu treatments to stop the viruses from spreading. It blocks the influenza virus from binding to the sugars on the cells' surface, which it needs to multiply and spread.

"Our drug agent uses the same approach as current flu treatments - by preventing neuraminidase from cutting its ties with the infected cell," UBC Chemistry Prof. Steve Withers, the study's senior author, said in a statement. "But our agent latches onto this enzyme like a broken key, stuck in a lock, rendering it useless."

"By taking advantage of the virus's own 'molecular machinery' to attach itself, the new drug could remain effective longer, since resistant virus strains cannot arise without destroying their own mechanism for infection," Withers said.

The drug was found to be effective when it was used to treat mice with lethal strains of the flu virus.

According to a report by the World Health Organization, influenza affects three to five million people globally each year, causing 250,000 to 500,000 deaths.

The findings of the study are published in the journal Science Express.