In December of 2013, a two-year-old boy in Guinea got sick. He vomited and experienced a fever and diarrhea. His mother, grandmother and sister cared for him and cleaned up his body fluids. Before the end of the month, they were all dead. Two years later, the virus that claimed their lives was responsible for the deaths of more than 10,000 people across Western Africa. As the number of cases sharply increased in the summer of 2014 and Ebola spread beyond the borders of West Africa, the public called for a vaccine.
They were unaware that a decade earlier a potential vaccine for Ebola had been shelved.
Between its discovery in 1976 and the epidemic in 2014, Ebola infected less than 2000 people, and the outbreaks were few and far between. But despite the low levels of infection, scientists recognized the dangers because of the high mortality rate––sometimes as high as 90 percent–– and started developing a vaccine. By 2006 the Centers for Disease Control and Prevention created a vaccine that passed the pre-clinical animal trials, showing that it could protect macaque monkeys from infection. But instead of proceeding to clinical trials in humans, development was halted.
“There was not enough funding, not enough research space, and not enough researchers who were engaged in this work,” says Dr. Nahid Bhadelia, the Director of Infection Control and Medical Response at the National Emerging Infectious Diseases Laboratory at Boston University, and an Ebola responder in Sierra Leone. “The vaccines existed at the animal model level, but for those reasons it didn’t move beyond that for many years.”
For public health agencies, it was difficult to justify spending hundreds of millions of dollars to make a vaccine for a virus that, before 2014, only caused small, isolated outbreaks. It was all about risk management, and more widespread and dangerous viruses, like Malaria, received more attention and more funding because it affected more people.
But as increased globalization changes the speed in which people around the world interact, and climate change altering the places viruses can inhabit, the viral world has gotten more connected. For health care workers like Bhadelia who saw the devastation of Ebola up close, this interconnectivity helped illustrate one important lesson: Instead of belatedly reacting to epidemics, society needs to be more active in preventing them.
For some of the more dangerous viruses, this could mean stepping up efforts to develop more vaccines. Diseases like Marburg, with a comparable mortality rate to Ebola, and Lassa Fever, which is endemic in the same region, are both considered ‘neglected’ diseases in terms of resource allocation by agencies like the CDC and WHO. Like Ebola, a vaccine for Marburg was in development in 2006, but was shelved due to lack of funding. Lassa, now experiencing an outbreak in Nigeria, affects between 100,000 and 300,000 people each year, and is responsible for 10 percent of the hospital admissions in West Africa. Vaccines for this virus have not proceeded past primate testing, despite positive trial results.
Tropical viruses, like Dengue Fever, have also been seen as growing threats as climate change enlarges the habitable zones of mosquitoes that transmit the virus, says Dr. Donald Thea, a professor of Global Health at Boston University. The other name for Dengue is break-bone fever because you get such intense aches and pains in your muscles where it feels like you broke your bones. This is one of the few ‘neglected tropical diseases’ that has a vaccine in the works, but the efficacy of the treatment is supposedly only moderate.
While the continued development of vaccines would stop, or slow massive outbreaks, they are only one factor that would decrease the risk of epidemics. The best protection against emerging pathogens is the establishment of strong public health and monitoring systems in countries where emerging epidemics will hit the hardest. This means West and Central Africa, Southeast Asia, and tropical regions of the globe, where viral hot spots between animals and humans are common.
But the public health systems in these countries are rarely equipped to deal with emerging epidemics, let alone track them. As witnessed with Ebola, Sierra Leone, Guinea and Liberia did not have the resources to contain the spread of the virus or even treat all of its victims. Distrust in health care workers and government officials prevented some communities from going to hospitals or even following quarantines, allowing the virus to spread further.
Instead, health care systems need to grow so they are fully capable of treating all the patients that require help. To better combat the spread of these dangerous viruses, doctors need to be able to quickly and accurately test for these different diseases so the government supported health systems can put out a coordinated public health response, says Bhadelia.
But while an improved health care system would help fight these emerging diseases, an advanced monitoring system could prevent outbreaks from becoming major epidemics in the first place. Currently, the WHO has a “network of networks” that link together local and international laboratories. Health Canada also has the Global Public Health Information Network that tracks reports about communicable diseases in online discussion groups, but their outbreak responses can still be delayed. Now, some researchers have started using social media posts or Google searches to track people posting about or searching for their symptoms online.
“History has taught us that there is always a new infectious disease around the corner,” says Thea. “The focus of public health has to be about establishing a very good global surveillance system.”
Creating advanced global surveillance systems in the most at-risk countries may be a long time away, and during an epidemic time is in short supply. So for now, researchers are starting to rely on tools we’ve had in our arsenal, but haven’t previously used. There were four potential vaccine candidates when the Ebola epidemic started. The WHO fast tracked one of these vaccines, called VSV-EBOV, and put into a clinical trial in Conakry, Guinea in March of 2015. The vaccine protected 100 percent of the people who received it, and the remaining villagers were protected through ring immunity.
According to Dr. Ana Maria Henao Restrepo, who coordinated the vaccine trial with the WHO, this ring-vaccination technique was the same strategy used to eradicate small pox, and its success relied on the support of the health care community in Conakry. The vaccine may have been delayed, but there was little doubt that it was a successful tool in the fight against Ebola.
“Over 200 young Guineans, doctors, nurses, statisticians and specialists who were brave enough to say ‘yes we will participate in this trial,’ went to treat families through this trial and train volunteers in good clinical practice,” Restrepo says. “This is what can happen if we pull together and communicate and combine our expertise.”
