The understanding of infectious diseases is beset by misconceptions and it’s time to clear the air
One hundred years ago, Pvt. Albert Mitchell, an Army mess cook stationed at Fort Riley, Kansas, US, received the very first diagnosis of a new strain of influenza that eventually infected approximately 500 million people across the globe – about one-third of the world’s population – and led to at least 50 million deaths, far more than the lives lost in the still-raging World War I. The Spanish flu pandemic brought new urgency to the quest to comprehend infectious diseases and the way they work, but the subject is still beset by scientific challenges and popular misunderstandings. Here are five of the most tenacious.
Myth No. 1: A pandemic on the scale of Spanish flu is unlikely today.
After the outbreak of H1N1 – or swine flu – in 2009, the World Health Organisation (WHO) warned that “the world is now at the start of the 2009 influenza pandemic.” Many researchers questioned that finding. Some said the WHO was unnecessarily raising anxieties; others suggested that the agency had been unduly influenced by the pharmaceutical industry, which would stand to make money in preparing for and treating an outbreak. A headline in a medical journal held that medical advances have made it “Unlikely That Influenza Viruses Will Cause a Pandemic Again Like What Happened in 1918 and 1919.” So what’s the truth?
It’s true that we’re much better than we were a century ago at detection and containment, we have antiviral drugs that save the lives of some infected patients, and the 575,000 lives that swine flu took were a small fraction of the Spanish flu total.
Most global health experts agree that it’s only a matter of time before a combination of risk factors makes us vulnerable to another pandemic.
We may even be overdue. Unlike in 1918, a disease can cross the globe in a fraction of the time it takes to show symptoms and before health officials realise that a crisis is brewing.
Increasing urbanisation worldwide, alongside weak health systems, means vulnerable people are living on top of one another. That’s the tinder epidemics need to explode.
Myth No. 2: Most healthy adults don’t need the annual seasonal flu vaccine.
The seasonal flu vaccine remains the best way to prevent infections. For millions, it can stave off serious complications and even death. Since 2010, influenza has resulted in up to 60.8 million illnesses, 710,000 hospitalisations and 56,000 deaths per year in the United States, according to the Centre of Disease Control. The seasonal flu vaccine also creates herd immunity, stopping the disease’s spread when a critical mass of people get vaccinated. Some protection is far better than none.
Unfortunately, manufacturers, which benefit from the current $3.3 billion seasonal flu vaccine market, have little incentive to invest in a universal vaccine that would protect against all forms of influenza.
Myth No. 3: Some of the deadliest pathogens don’t pose an immediate risk.
It’s easy to think that measles is no longer a threat, since The US Centre for Disease Control (CDC) declared that it had been eliminated from the United States in 2000.
In America alone, about 1 in every 20 children with measles gets pneumonia, 1 of every 1,000 gets encephalitis, and 1 or 2 out of 1,000 will die. Unless we’ve eliminated measles — and, for that matter, other infectious diseases such as polio and diphtheria — everywhere in the world, people will remain susceptible to them. The reality is:
An error some epidemiologists make is to focus on the near crisis at the expense of the far one. In 2014, when the Ebola epidemic raged in Africa, pundits called it the “ISIS [Daesh] of biological agents,” the US president sent troops to Africa and Congress held hearings. Yes, Ebola is an incurable, often-lethal malady with no licensed vaccine, but it’s hard to transmit from person to person and an unlikely candidate for a pandemic. It is a mistake to treat it with so much urgency that we fail to neutralise other potential threats.
Today’s vaccines prevent fewer than 30 human pathogens. But since 1940, researchers have identified more than 340 new diseases, and the number of annual outbreaks globally has increased from fewer than 800 in 1980 to more than 3,000 by 2010.
The WHO warns that several emerging pathogens with few or no medical countermeasures may cause havoc in the near future, including such nasty ones as Crimean-Congo haemorrhagic fever, Ebola, Marburg virus disease, Lassa fever, MERS and SARS coronavirus diseases, Nipah, and Rift Valley fever. That doesn’t include other potentially epidemic diseases such as HIV/AIDS, tuberculosis, malaria, avian influenza and dengue fever, which already have major disease-control efforts but still would benefit from effective vaccines.
Myth No. 4: We need bigger vaccine stockpiles to neutralise disease outbreaks.
When yellow fever appeared in Angola and spread to Congo in 2016, the global yellow fever vaccine stockpile was not nearly big enough to give everyone there a full dose. Many have called for expanding the size of that stockpile, and it is a common subject of debate for a range of infectious diseases.
But logistical and economic challenges limit the size of any vaccine stockpile. It’s a complex business to get it just right.
Egg-based vaccines, for example, are hard to scale up quickly; vaccines have a shelf life; and producing large quantities of vaccines that may never be used can be expensive and can take scarce resources away from routine immunisation.
Rather than focus too much on stockpiles, government and nongovernmental organisation money would be better spent helping struggling countries immunise their populations to prevent infection. They should also build health systems capable of detecting and responding to outbreaks before they spread further – the objective of a valuable CDC global health initiative that’s now in danger of substantial downsizing.
Myth No. 5: Barring people from disease-affected countries will keep the nastiest bugs out.
At the height of the Ebola outbreak in 2014, a number of American public figures urged closing US borders to travellers from the hardest-hit West African countries. “The bigger problem with Ebola is all of the people coming into the US from West Africa who may be infected with the disease. STOP FLIGHTS!” tweeted Donald Trump, then a private citizen.
Such responses rarely work; pathogens don’t respect borders.
Efforts by countries to ban flights from nations with H1N1 outbreaks in 2009, for example, were ineffective, according to a 2011 study in the journal PLOS One. Also, cutting off contact with outbreak-affected countries can compound the problem by grounding supplies and personnel they need to fight the spreading disease.
Most countries already take precautions to ensure that potential pathogens don’t cross borders: They require travellers to show immunisation records or report symptoms, and subject them to thermal temperature scans at ports of entry.
There’s no real substitute for preventing outbreaks at their source, through routine immunisation, improved surveillance and other proven public health measures.
(Seth Berkley, a physician and epidemiologist, is CEO of Gavi, the Vaccine Alliance.)
The Washington Post