Wednesday, December 7, 2016

The recent African yellow fever epidemic and vaccination campaign failures

From December 2015 to September 2016, Angola and the Democratic Republic of Congo battled a resurgence of yellow fever. The outbreak received very limited attention because the world was turned toward the zika virus epidemic. However, that doesn’t mean it wasn’t alarming. In fact, the World Health Organization almost declared yellow fever a global emergency on May 19, 2016. Fortunately, the epidemic began to slow.

When the virus first struck Angola, doctors misdiagnosed cases as food poisoning. To further complicate matters, labs capable of testing blood samples for yellow fever virus were far away, which ultimately played a role in how slow the outbreak was reported to officials. There were approximately 1,000 lab-confirmed cases and 6,000 suspected cases. It is likely that many more were unreported. In order to control the outbreak, Doctors Without Borders sprayed homes in the Democratic Republic of Congo with pesticides to control mosquito populations. Additionally, mass vaccination campaigns began.

Alarmingly, Angola’s government only had enough yellow fever vaccine stockpiled to vaccinate less than one city. Several countries like Brazil and South Sudan donated some of their stockpile to help vaccinate people in affected areas. Ultimately, the vaccines that were given had to be diluted in order to ensure enough for everyone. Vaccine manufacturers also increased production. Unfortunately, because profits are so low, there are currently only 6 companies who are capable of manufacturing the vaccine, only 4 of which sell to WHO.

The virus was transmitted to Peru in May 2016, but the country was able to control the outbreak successfully on their own. Additionally, 11 Chinese people who had worked in Africa contracted the virus and brought it to China. This was significant because many Chinese people work in Africa and travel back and forth, China has the proper mosquito vector to transmit the virus, and most importantly, the yellow fever virus has never before reached Asia, which means the entire continent is vulnerable due to its lack of immunity.

If the virus were able to gain foothold in China, there is no doubt that yellow fever would have replaced ebola and zika in the headlines. It was estimated that a minimum of 160 million vaccines would be needed to control the outbreak, if the vaccine were still effective diluted 10-fold. Due to limited manufacturing capacity, only half that much could be produced in a year.


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