It's too soon to declare victory over Ebola

This was originally published at Global Health TV on Aug. 24, 2015.

There has been a welcome spate of good news coming out of West Africa in recent weeks on the apparent demise of Ebola, which has caused the region nothing but misery, illness (27,952 reported cases) and death (11,284 reported deaths) for over a year.

Ebola cases continue to fall. For the week ending Aug. 16, no new cases were reported in Liberia and Sierra Leone, for the first time, has gone one full week without any new cases. Guinea was the only country to report any new cases — but just three.

And The Lancet published “interim results” from research on the efficacy of an Ebola vaccine in Guinea showing a vaccine efficacy of 100%.

The news is undeniably good. In the last week, I read these headlines:

Associated Press: “UN official: Ebola epidemic could be defeated by end of 2015.”

Scientific American: “Does This Ebola Vaccine Herald the End of the Virus?”

National Public Radio: “Zero Ebola Cases Reported in Sierra Leone as Epidemic Peters Out”

This is all welcome news but if you go beyond the headlines you quickly realize that this epidemic is not yet over.

The World Health Organization, in its most recent Ebola situation report of Aug. 19, cautions against premature declarations of victory in the very first paragraph:

“However, there is still a significant risk of further transmission. In addition to the large number of contacts who remain under observation in Guinea and Sierra Leone, 45 contacts have been lost to follow-up in the Guinean capital Conakry over the past 6 weeks. Several high-risk contacts have also been lost to follow-up in the Sierra Leonean capital, Freetown. Rapid-response teams remain alert and ready to respond to further cases.”

Until all of these contacts pass the 21-day follow-up period, there is every reason to suspect more Ebola cases. And the vanished contacts in Conakry and Freetown are cause for concern.

Virologist Ian Mackay of the Australian Infectious Diseases Research Centre writes in this blog that this good news is subject to caveats.

“Those blissful stretches [of zero cases] may be punctuated by a case arising from parts unknown. They may be tracked to a sexual transmission event, or their origins may never be fully understood … So we’re not at all free and clear of this virus yet. It’s still a long haul with many weeks of anxious waiting and heightened vigilance as well as the need to retain the capacity to cope with new cases. But, that said, we do seem to have taken one more step back from the precipice we once started into as we imagined an Africa fending off a rolling Ebola epidemic.”

And as for the exciting news of the Ebola vaccine with 100% efficacy, this article on WIRED explains why that number means less than you think. One of the problems is that the findings are based on incomplete data, according to WIRED. Another challenge is that since the vaccine was tested while the epidemic was receding, it is difficult to know if the vaccinated people who didn’t develop Ebola in the trial were protected by the vaccine or simply benefited from the decline of the epidemic.

Clearly, this is a breakthrough (for there is nothing else available against Ebola) and very encouraging. But, just as clearly, more data is needed to know how efficacious this vaccine really is. And then there’s the significant challenge of getting the vaccine to those who need it once we know that it works.

The other major challenge is to restore, and then strengthen, the health systems of Guinea, Liberia and Sierra Leone, which were weak even before the epidemic. It will be hard to do that without well-trained and well-motivated health workers. Their ranks were decimated by Ebola: A little-reported fact of the epidemic is that the three countries reported 880 confirmed health worker infections since the start of the outbreak, with 512 deaths, according to the WHO.

Craig Spencer, a doctor from New York who was one of four people stricken with Ebola in the U.S., addressed this challenge in The New York Times last week:

“If the epidemic’s immediate impact on the West African health system sounds dire, the probable consequences are even more unsettling. Immunization levels have dropped across all three countries, so that, for instance, a regional measles outbreak could cause hundreds of thousands of cases — and potentially more deaths than Ebola. A recent World Bank report estimated that maternal mortality could skyrocket, setting the entire region back with rates not seen in almost two decades.”

Just restoring the health systems to what they were before Ebola will be a huge challenge. Improving them beyond that status quo, so they are better able to deal successfully with epidemics of the future will be even more daunting. But it must be done. The governments of the three countries must lead the way, with significant help from the international community.