The Zika virus and the Ebola virus have received a lot of attention in the media lately, but they’re unlikely to cause a global pandemic disaster, says a new report from Johns Hopkins Bloomberg School of Public Health in Maryland. Instead, the thing to watch out for are airborne viruses, including those related to the flu and the common cold, reveals the research.
Led by Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security in Baltimore, the study examined the characteristics of pandemic pathogens in order to understand what the next pandemic would look like.
Contrary to general expectations, Zika and Ebola — which spread through contact with bodily fluid and, in the case of Zika, mosquito bites — were not high on the list of possible threats.
The real danger comes from respiratory viruses, Adalja points out.
“We need to get serious about respiratory viruses,” he told LiveScience.
“There’s a lot of focus on diseases that aren’t going to be able to change civilization in a way that something that’s spread through the respiratory route would be,” Adalja explained.
His research uncovered that the next global pandemic will most likely be caused by a group of viruses known as RNA viruses, which have ribonucleic acid (RNA) as their genetic material.
This group encompasses both viruses that have caused outbreaks in the past, such as influenza and severe acute respiratory syndrome (SARS), and common cold viruses, such as enteroviruses and rhinoviruses. The respiratory syncytial virus, one of the major culprits behind lung and respiratory tract infections, is also on this list.
— Amesh Adalja (@AmeshAA) May 12, 2018
The reason why RNA viruses have the most potential to bring about the next pandemic is that they mutate more easily than other types of viruses. In addition, they fit the other pathogen criteria that could lead to a global disaster, as uncovered by the study.
Traits Of The Next Pandemic Pathogen
According to the new research, a pathogen with the ability to disrupt a large portion of the world’s population would have to be airborne and be contagious during its incubation period, before people catch on to the symptoms or only exhibit them in minor, unalarming degrees.
This pathogen X would also have to be a microbe that most people don’t have immunity to so that it would have a bounty of human hosts and spread rampantly within the population.
Another important characteristic that would make this virus a potential worldwide threat is the lack of an existing treatment or prevention method — which is already true in the case of many RNA viruses.
But perhaps the most significant criterium underlined by the study is that pathogen X would need to have a “low but significant” fatality rate.
Adalja explains that a virus can disrupt society without killing the majority of people it infects.
“It just has to make a lot of people sick.”
In fact, according to something known as the “host density threshold theorem,” a pandemic pathogen needs to have a low fatality rate because it would run out of hosts and end up being extinguished if it were to produce a high death toll.
For instance, the 1918 Spanish influenza pandemic, described by the Centers of Disease Control and Prevention as “the mother of all pandemics,” only had a fatality rate of 2.5 percent but ended up killing an estimated 50 million people because it spread to a staggering number of hosts.
How To Prepare For The Next Pandemic
As LiveScience points out, health authorities typically have a list of “usual suspects” — a number of viruses on which they keep an eye on because they are historically known to cause outbreaks. This list normally includes influenza and SARS, as well as viruses that have the potential to become biological weapons.
However, unknown viruses such as pathogen X or those that haven’t caused major outbreaks in the past should also be monitored, underlines the new report.
— Microbiology Conference (@microbio_2018) May 11, 2018
Adalja states that there is “a whole host of viral families that get very little attention when it comes to pandemic preparedness” and calls for a stricter surveillance of all RNA viruses, not just influenza.
According to the study, the best strategy to get in front of a future pandemic is to develop antiviral drugs and vaccines that specifically target RNA respiratory viruses, as well as a universal flu vaccine.
Another important measure is to improve the way patients are tested when they check into the hospital with certain symptoms, in order to pinpoint the exact infectious cause.
This type of preventive measure is extremely necessary, considering the next pandemic could start off with relatively mild symptoms, Adalja reveals.
“It’s not always going to be somebody dying a horrible death. It could be a very minimal case.”
Since “it is unclear where the next pandemic pathogen will appear,” the report recommends that this type of testing be performed routinely, in order to confirm exactly what pathogen is at fault when patients come in with a nasty cough or difficulty breathing.