Bird Flu Outbreak Could Be a Threat to Humans, Warns UN: What Does It Mean?

Bird Flu Outbreak: Why doesn't India permit vaccination in poultry?

What to know about bird flu: vaccines, prevention, outbreak

(Image: iStock)

Three United Nations (UN) agencies have warned that surging outbreaks of bird flu in various parts of the world could potentially increase the risk of the virus evolving to infect humans more easily.

Since the begining of the year, a new, highly contagious strain of bird flu (H5N1) has been spreading rapidly among birds, and even mammals in new geographical regions, raising fears of a potential outbreak among humans.

In order to keep the situation from getting out of hand, the World Health Organisation (WHO), the United Nations' Food and Agriculture Organization (UN FAO) and the World Organisation for Animal Health (WOAH) have made statements saying countries should work together to control infections among birds, and protect people.

They have also called for genetic data of the virus to be made available in public databases for easy access.

As more and more cases of bird flu pop up in mammals around the world, should we be bracing ourselves for another possible pandemic? Is there a vaccine for bird flu?

FIT explains.

Situation Right Now: Which Countries Are Affected?

These new cases of bird flu have raised concerns as they were found to be caused by an older clade (2.3.2.1c) of the H5N1 strain, which emerged in 2020 and has caused record numbers of deaths among wild birds and domestic poultry in recent months.

According to reports, so far the virus has led to the death of 208 million birds around the world.

This outbreak of bird flu has affected large batches of poultry in the US, UK, Canada, Japan, France, Portugal and other parts of Europe.

Speaking to the press earlier this month, the Union Minister of Fisheries, Animal Husbandry and Dairying, Parshottam Rupala confirmed that bird flu in commercially reared and wild birds have been detected in 14 states in India so far, including Kerala, Haryana, Madhya Pradesh, Maharashtra, Chhattisgarh, Gujarat, Uttar Pradesh, Uttarakhand, Punjab, Himachal Pradesh, Bihar, Rajasthan, Delhi, and Jammu and Kashmir.

What Makes the Current Outbreak Different From Past Ones? 

Bird flu cases are known to spike from time to time, especially during the winter months. However, the ongoing outbreak has experts on edge as it is the longest-running outbreak of bird flu in history.

The dominant variant this time around, H5N1 has been found to be more transmissible and not deterred by the heat in the summers that usually subsides the spread of the virus.

This year, the virus has been, uncharacteristically so, found in a number of mammals including:

• Grizzly bears in the US

• Mink in Spain

• Sea lions in Peru

• Otters foxes in the UK

This time around instances of the outbreak spilling over to mammals has led experts to question how easily this variant is able to jump from poultry to mammals, and spread from mammal to mammal.

Can It Become a Pandemic?

According to the WHO, in the past 20 years, 870 humans have been infected with bird flu, and 457 have died.

Although it's very contagious among birds, the H5N1 strain has also only infected a few humans so far. All of them had close contact with infected birds, and most of them have been mild.

Health authorities continue to maintain that of now the threat to humans remains low.

The possibility of the virus spreading among humans rapidly will arise if the existing strains mutate to be able to spread from human to human, which is why, according to experts, incidence of infections in mammals must be monitored closely, and robust genome sequencing data must be gathered.

Though sporadic cases have been detected in humans in some countries, according to the US Centres for Disease Control and Prevention (CDC), currently there is no indication of human-to-human transmission.

Is There a Vaccine?

There are vaccines for poultry against highly pathogenic avian influenza (HPAI), but poultry farmers in many countries have been reluctant to use them. There are a few reasons for this.

• The vaccines help reduce death, but it doesn't necessarily stop infection and transmission of the virus.

• Even vaccinated birds need to be monitored and tested, and those suspected to be infected would still need to be quarantined, culled.

• Bird flu is known to mutate rapidly, which means the efficacy of vaccines can wane quickly.

• Vaccinating large flocks of poultry can be expensive and time-consuming, as shots often need to be administered individually.

According to the World Organisation for Animal Health (WOAH) , just vaccination is not sufficient to restrict the spread of the disease. It must be used in tandem with other preventive disease control measures such as culling, movement restrictions and surveillance.

Some countries have banned import of vaccinated poultry out of fear of infected birds slipping through.

For this reason, countries like the UK, and the US – some of the largest producers of poultry meat in the world – do not allow for the use of vaccines for fear of it impacting trade with very little benefit.

India, too, does not permit the use of bird flu vaccine.

Given the trade restrictions on vaccinated poultry in many countries, fresh bilateral negotiations would be needed to allow exports to those markets and avoid unfair competition, Philippe Gelin, chief executive of one of Europe's largest poultry firms, was quoted as saying by Reuters.

That said, countries like the US, UK, and France are still testing out vaccines.

Are There Vaccines for Humans?

Although vaccines do exist, vaccinating humans against bird flu is tricky because we don't know yet which variant or subvariant of the virus (if any) is capable of human-to-human transmission.

• Unless we know which variant to make the vaccine against, a general vaccine would not be adequately effective.

• Moreover, the avian flu virus mutates so fast, it would be difficult to vaccinate against them all.

However, studies and clinical trials are underway. In 2022, a paper published in the medical journal Science showed that a flu shot against all 20 known subtypes of influenza A and B virus protected mice and ferrets against several strains of flu.

France's Ceva Animal Health, one of the top companies developing bird flu vaccines in the world has said that they are developing an mRNA vaccine, similar to the COVID-19 vaccines, for bird flu as well, reported Reuters.

What is the WHO saying?

"There is a recent paradigm change in the ecology and epidemiology of avian influenza which has heightened global concern as the disease spread to new geographical regions and caused unusual wild bird die-offs, and alarming rise in mammalian cases," said Dr Gregorio Torres, Head of the Science Department at WOAH, in a statement released by the WHO.

According to the WHO, the virus is being closely watched for any changes that may help it spread more easily among humans.

"WHO is working closely with FAO and WOAH, and laboratory networks to monitor the evolution of these viruses, looking for signals of any change that could be more dangerous to humans," added Dr Sylvie Briand, Director of Epidemic and Pandemic Preparedness and Prevention, WHO.

"We encourage all countries to increase their ability to monitor these viruses and to detect any human cases."

Dr Sylvie Briand, Director of Epidemic and Pandemic Preparedness and Prevention, WHO

It also added that in order to avoid being blindslided if the situation escalates, governments and pharmaceutical companies should invest in developing vaccines for all strains of influenza virus that exist in the animal kingdom.