More proactive flu strategy needed

By Su Ih-jen 蘇益仁  / 

Fri, Jan 12, 2018 - Page 8

In the past couple of weeks, the number of seasonal flu cases has seen a steep rise. The dominant circulating virus has been of the Yamagata lineage, which is different from the vaccine strain of the Victoria lineage recommended by the WHO. As a result, the effectiveness of the protection offered by the vaccine has dropped to only 30 percent of its original expectation and led to a massive epidemic, despite the fact that 7 million shots — the highest amount in the past few years — were administered last year.

Faced with the difficult situation caused by the epidemic virus strain differing from the virus strain that the vaccine is intended to protect against, medical experts suggest that quadrivalent flu vaccines should be given so as to provide protection against the two types of influenza B.

However, the price for one dose of quadrivalent flu vaccine is NT$2,000 and it is not covered by the National Health Insurance.

For the time being, the government might first make the quadrivalent vaccine available only to high-risk groups for flu infection as a measure of expediency. If there are any problems, the government should follow the measures they adopted in February 2016 to loosen restrictions on the eligibility of receiving government-funded antiviral drugs for people diagnosed with the early phase of flu (within 24 to 48 hours).

Otherwise, a massive flu epidemic could break out around Lunar New Year and have a huge impact not only on people but also on the medical system.

According to a report in Time magazine on Dec. 25 last year, there was a severe epidemic of influenza A in Australia last winter that resulted in nearly three times as many cases as compared to the same period of the past few years.

The main reason for the epidemic was that the H3N2 and H1N1 viruses growing in chicken eggs that were selected for manufacturing the vaccine underwent mutations, which reduced the effectiveness of the protection provided by the vaccine.

Even so, experts still recommend that the vaccine continues to be administered for the purposes of alleviating symptoms and lowering the spread of flu. Influenza A was prevalent in Taiwan last year from June to August, which is an unusual timefor flu, and during this time the same kind of virus mutation in eggs was also observed.

Up to the time of writing this article, patients suffering from influenza A account for only about 20% of total flu infections, but the possibility that the number of cases will increase cannot be ruled out and close attention should be paid to developments.

If the influenza A and two mutated influenza B viruses simultaneously become epidemic, leading to a huge flu outbreak, it would be difficult to estimate the consequences.

In addition to seasonal flu, several outbreaks of highly pathogenic avian influenzas such as H5N2 and H5N6 have been reported in southern Taiwan at the very beginning of this year. Tens of thousands of chickens and ducks have been culled by the Council of Agriculture, but future prospects still do not look very promising. Whether these highly pathogenic avian influenzas have developed — or might develop — the possibility of transmission from bird to human, as happened with H7N9 in southern China, should be attentively supervised and controlled by the government.

I have previously advised the Executive Yuan to establish a central epidemic command center for avian influenza, as they did for preventing dengue fever, in order to coordinate the supervision, diagnosis and prevention of an epidemic, as well as culling infected livestock and conducting vaccine research and development.

Unfortunately, the council only dealt with the issue by implementing a project and saying that the advice would be evaluated.

Flu epidemics in Taiwan are special in that the specific virus strain of the seasonal flu in Taiwan is identified two years before the virus strain selected by the WHO for manufacturing vaccines. The WHO selection is based on European and American virus strains, so as much as 40 percent of WHO-recommended vaccines are “wrongly predicted,” as the virus targeted by the vaccine does not match the dominant virus that is circulating in Taiwan.

Adding influenza virus strains from Southeast Asia into the consideration when making vaccines has been continuously proposed to the WHO for 10 years, but always comes to no avail. It is time that Southeast Asian countries establish their own database of virus strains, share research findings and collaboratively develop flu vaccines targeted at a virus strain different from the one selected by the WHO.

The government should follow the example of Japan’s National Institute of Infectious Diseases and establish a central epidemic prevention and research center to designate preventive measures and conduct influenza research, so as to be able to react effectively to virus mutations and the threat of bird flu.

In preparation for a possible flu outbreak in the spring, the government should assess their inventory and evaluate the administration of the quadrivalent flu vaccine.

The prevention of epidemic disease is a war against the virus, and we need to be a step ahead of the enemy in order to win.

Su Ih-jen is a distinguished professor in the Department of Biotechnology at Southern Taiwan University of Science and Technology.

Translated by Chang Ho-ming