Drug company Merck hopes to have a licensed serum ready for use next year.
Results from clinical trials of the first vaccine designed to prevent Ebola indicate the serum is highly effective, giving world health experts hope for preventing another major outbreak of the deadly disease.
According to a study published in The Lancet, medical researchers gave the vaccine to 5,837 people in Guinea during 2015. The physicians vaccinated one group of 3,796 people immediately after they had come in contact with an infected person or had come in contact with someone who had direct contact with an infected person. The other 2,041 subjects received the vaccine after a three-week delay.
No one in the immediately vaccinated group developed Ebola, but 23 of the subjects who either received the delayed vaccination or no vaccination at all contracted the disease. The researchers concluded the vaccine had a 100 percent efficacy rate.
“While these compelling results come too late for those who lost their lives during West Africa’s Ebola epidemic, they show that when the next Ebola outbreak hits, we will not be defenseless,” Marie-Paule Kieny, assistant director-general for Health Systems and Innovation, and the study’s lead author, told the World Health Organization (WHO).
Ebola outbreaks continued to plague Guinea in 2015 when the trial took place. The researchers used what is called a ring vaccination approach, the same method used to eradicate smallpox. After each new Ebola diagnosis, the team traced the entire ring of people who might have been in contact with that person during the previous three weeks, including people who had come into close contact with the patient’s clothes and linens, or the contacts of contacts. They identified a total of 117 rings.
At first the researchers offered the vaccine only to those over age 18, but after the initial results showed its effectiveness, they offered it to all rings immediately and opened the trial to children older than 6.
About half the people who received the vaccine reported mild side effects, including headache, fatigue, and muscle pain that resolved within days. Two people experienced serious events, one involving fever and the other an allergic reaction. A third case of influenza-like symptoms may have been related. No subject suffered any long-term effects.
The manufacturer, Merck, Sharpe & Dohme, plans to submit the vaccine for licensure by the end of 2017. In the meantime, it has committed to making 300,000 doses available for emergency use. Merck also submitted the vaccine to WHO’s Emergency Use and Assessment Listing procedure, a process that can make the serum available for use prior to licensure. Researchers will continue to study the safety of the vaccine for children and other vulnerable populations.
The most widespread outbreak of the virus occurred in West Africa between 2013 and 2016, killing more than 11,300 people. At that time, doctors had no prevention or widely accepted treatment available. One of the first U.S. physicians to contract the disease while treating patients in Africa has returned to work. Missionary Kent Brantly, who was stationed in Liberia, is now practicing medicine and teaching at John Peter Smith Health Network in Fort Worth.
Brantly told Fort Worth’s Star-Telegram that his experience with the disease underscored the world’s interconnectedness: “Anything happening somewhere around the world—any epidemic, disaster, humanitarian crisis—it can show up at our doorstep in the blink of an eye and we have to be prepared for that.” But the most important thing he learned was how vital it is to choose compassion over fear.
“I talk about that from the perspective of my religious faith, the teachings of Jesus to love your neighbor as you love yourself,” said Brantly, who hopes to serve overseas again some day.
— by Julie Borg