CNA Explains: Bird flu is spreading globally. How worried should we be?

SINGAPORE: In June, authorities in Singapore warned against touching or feeding wild birds - including free-roaming chickens - as a precaution against avian influenza or bird flu.

Weeks later, the United States gave US$176 million to pharma giant Moderna to advance development of a bird flu vaccine. This would be based on the same mRNA technology used for COVID-19 jabs – in a pandemic still fresh in the memory.

What is bird flu?

It’s a virus that was discovered nearly 150 years ago, back in the late 1800s, and has been spread among migratory water birds since.

At some point it also crossed over to farm animals and domestic poultry - which can become very sick and die from bird flu. Human cases are rare but can result in severe and possibly life-threatening illness.

Among several sub-types or strains of bird flu, the ones that have affected humans the most are H5N1 and H7N9.

Why is it in the news now?

The World Health Organization (WHO) has voiced concerns over H5N1’s growing spread of late. 

It has killed or led to the culling of hundreds of millions of poultry globally in recent years, upsetting food supply chains in some cases. And it has increasingly been infecting mammals not previously thought susceptible, from alpacas to house cats.

In the US, the virus has struck more than 130 cow herds and three dairy workers.

Australia meanwhile is battling outbreaks at 11 farming facilities, all involving virus strains different from H5N1. It’s led to an egg shortage and prompted McDonald’s to cut breakfast service timings by 1.5 hours.

Other cases of human infections have been reported in Mexico, India and China. There are no known instances of the virus in Singapore so far.

Researchers have pointed to climate change as a factor in the spread, with fluctuating temperatures altering bird migratory and breeding patterns. 

Habitat destruction and urbanisation are also increasing human contact with animals, and it will probably become more common to see viruses spilling over into humans, said Professor Ooi Eng Eong from the Duke-NUS Medical School’s emerging infectious diseases programme. 

“Our ability to detect such viruses has also improved greatly … We have a lot more tools,” he added. “We can detect these events (which) 50 years ago were probably unheard of.”

Should humans be worried?

Bird-to-human transmissions are relatively rare. The few cases reported overseas were exposed to infected birds and poultry or contaminated environments.

The WHO has said H5N1's risk to the general population is low because there's no evidence of human transmission. 

But that doesn’t mean the chances of it happening are zero.

"It is definitely possible," said Prof Ooi.

He cited an experiment some years ago, where researchers attempted to find out how many adaptations were needed for H5N1 to be transmitted from ferret to ferret. The creatures are often used to study respiratory diseases as they contract the same viruses as humans, and their lungs and airways are physiologically similar.

“The answer is not that many,” said Prof Ooi. “It may just be a few mutations away. And that's why we need to take H5N1 seriously.”

When humans do catch bird flu, the fatality rate is high, with WHO data over the last two decades showing that H5N1 for one has killed about half of almost 900 people infected with it.

The symptoms are quite similar to COVID-19, according to Prof Ooi. These include fever, cough and in some cases, shortness of breath and tightness of the chest.

So is it safe to consume chicken, eggs or milk?

In Singapore at least – yes, said Prof Ooi, pointing to the Singapore Food Agency tightly controlling imports and ensuring overseas sources follow biosecurity protocols.

Late last year, for instance, Singapore suspended the import of raw poultry and poultry products from several countries affected by H5N1 outbreaks.

But that might not be the case in other countries, Prof Ooi added, echoing warnings issued by local authorities earlier in June. 

Singapore's Health Ministry (MOH) has strongly advised travellers not to go to live bird markets or dairy farms when abroad, and not to consume uncooked meat or raw milk. 

How is bird flu treated?

According to MOH’s website, the antiviral medication Tamiflu is often the go-to treatment.

In the preemptive space, Finland meanwhile is expected to become the first country to offer vaccines to workers exposed to animals.

On Saturday (Jul 6), MOH told CNA there were currently no plans to vaccinate high-risk people in Singapore.

A spokesperson pointed to how the WHO also doesn't recommend vaccinations for humans, due to human infections being “rare and limited”.
 
“The usefulness of avian influenza vaccines is dependent on whether the vaccine closely matches the avian influenza virus strains that may circulate in Singapore in future, but influenza virus strains continually change,” he added.

Could bird flu cause the next pandemic?

Should a day come when the bird flu adapts and gains the ability to transmit efficiently from animals to humans; and then from humans to humans – that would be the beginnings of a pandemic, said Prof Ooi.

He noted that influenza has been behind major pandemics in history, with three in the last century and the biggest being in 1918, which killed about 60 million people.

A Reuters report on Jul 1 said several leading scientists were increasingly concerned that gaps in surveillance and testing for bird flu might keep the world several steps behind in responding to a new pandemic.

Singapore, while free of the bird flu for now, shouldn’t take things for granted and should be prepared with plans in place that can be quickly ramped up, said Prof Ooi. 

For one, with the COVID-19 pandemic demonstrating that vaccines can be made quickly, Singapore and its neighbours should build up such capabilities so there's no need to “queue up" to buy jabs from Europe or North America, he noted.

The researcher also stressed the importance of having first responders and disease control professionals aware of what they need to do, rather than “make it up” as and when a pandemic happens.

“We need to keep engaging the population as well so that they are aware of what they need to do when it does happen,” he said.

On that front, he has observed that people are “more or less slowly sliding back” to pre-COVID days, when they cared less about wearing a mask or taking time off work when unwell.

Should the bird flu emerge as a serious public health concern, said Prof Ooi, one must hope that the people "can very quickly go back to some of those precautions”.