Ebola vaccine put to the test in DRC
The first case of Ebola ever recorded, in 1976, was near the Ebola River in the Democratic Republic of Congo (DRC), which flows into the Congo River.
On the east bank of the Congo River is Mbandaka, the capital of Équateur province, now a focus of concern for the country’s health ministry and other public health organisations after four new Ebola cases were confirmed there.
This is the DRC’s ninth Ebola outbreak in four decades.
The four Mbandaka cases, reported last week, brought the number of casualties recorded between April 4 and May 21 up to 58. This number includes three healthcare workers, one of whom died on Monday.
In a statement released on Friday last week, the World Health Organisation (WHO) said the Mbandaka cases signal the risk of a more rapid spread of the illness because of the city’s proximity to the Congo River, which has significant regional traffic across borders.
Most cases have been in the remote market town of Bikoro but Mbandaka has a population of 1.2-million.
For this reason, 7 540 doses of the rVSV-ZEBOV Ebola vaccine were deployed to the DRC. A treatment centre in Mbandaka was the first to get the experimental vaccine, which was administered to 33 people on Monday. The vaccine will travel about 130km to Bikoro on Thursday.
The vaccine was first rolled out during a 2015 clinical trial in Guinea and Sierra Leone as a response to the deadliest Ebola outbreak in history, between 2014 and 2016. More than 11 000 deaths were reported across West Africa during this period.
The trial results, published in medical journal The Lancet in December 2016, declared the vaccine highly protective against Ebola.
Among the 5 837 people who received the vaccine, no Ebola cases were recorded 10 days or more after vaccination. In comparison, there were 23 reported cases among those who did not receive the vaccine.
The current immunisation programme will be administered as what is called “ring vaccination” and will be carried out in a co-operative effort between the DRC’s health ministry, the WHO and Doctors Without Borders (MSF).
WHO spokesperson Tarik Jasarevic told the Mail & Guardian that the vaccine will not be administered in a general campaign for the whole population of the affected area but will instead target those at the highest risk of infection.
This includes people who have been in contact with confirmed cases, and the contacts of contacts, meaning roughly 150 people are vaccinated for every confirmed case, Jasarevic said. These groupings are called rings.
After receiving the candidate vaccine, they will be followed up on for a set period of time.
A later study, also published in The Lancet, concluded that carrying out such an undertaking in resource-limited rural areas is feasible, but there are significant logistical challenges.
The tropical heat of the DRC means that keeping the vaccine at the required –60°C to –80°C is of major concern to those conducting the project. Jasarevic said the WHO has sent special vaccine carriers, which can keep their contents in sub-zero temperatures for up to a week, and has set up freezers to store the vaccines in Mbandaka and Bikoro.
Transporting the vaccine is another obstacle. An air bridge between Kinshasa, Mbandaka and other more remote areas has been put in place; flights will operate six days a week to deliver supplies.
MSF medical director Micaela Serafini told the M&G that the people who get the vaccine must fully understand the vaccination process. This includes carrying out follow-up appointments and establishing an understanding of the vaccine’s potential side effects.
“It is important that we reassure communities that generic side effects — fever, diarrhoea, vomiting — are totally normal,” Serafini said.
She emphasised the importance of informed written consent. In previous trials, some within the rings have refused to consent to vaccination because the vaccine is still unlicensed, she said.
“The ethical concerns of rolling out the vaccine go hand in hand with the vaccine not yet being registered,” Serafini said. “So expanded access and very thorough consent protocols must be followed.”
Serafini, who has been vaccinated, said she is “confident that the vaccine works” but added: “There must still be space for those eligible to receive the vaccine to say ‘no’.”