(5 804 475 of 6 583 216); promed reported that the total national stock of yellow fever vaccine as of 29 mar 2016 was 1 032 970 doses. as of 10 april 2016, almost 6 million people had been vaccinated in luanda. on 19 april, the who reported that the campaign had been extended into the provinces of huambo and benguela where local transmission was reported. on 23 may, the who reported that 7.8 million people (91.1%) had been vaccinated in the three provinces. on 23 may, the who announced that coverage of an additional 2.7 million people in 5 provinces had reached 55% after 6 days of vaccination. if the epidemic were to spread, particularly into asia, the global supply of vaccine would have been insufficient to protect the millions of people that would need to be vaccinated to curb an epidemic. as an emergency measure, experts suggested the dose-sparing strategy to extend existing supplies of vaccine, which the who could provide under the emergency use assessment and listing procedure. the who agreed to the recommendation in june 2016, authorizing one-fifth the usual dose during the ongoing outbreak in angola and dr congo, but international health regulations still apply to travelers, who must obtain the full dose to quality for the certificate of vaccination. on june 22, the who announced plans to launch a pre-emptive emergency vaccination campaign beginning in july in highly trafficked borders areas of angola and dr congo and in densely populated kinshasa. on 20 july, the dr congo government launched a campaign to deliver 1 million doses of yellow fever vaccine over 10 days. in august, the who with partners including médecins sans frontières, international federation of the red cross and unicef launched another campaign to vaccinate more than 14 million people in angola and dr congo. on 2 september, who announced that the campaign to vaccinate the 7.7 million residents of kinshasa, the capital of dr congo, had been completed in record time and before the beginning of the rainy season in september when the mosquito population expands. the campaign required 10 million specialized syringes and training of 40,000 vaccinators, using the dose sparing strategy of 1/5 the usual dose. later studies found that the one-fifth-dose vaccine was just as protective as the full dose, even 10 years after the vaccination. in august it was reported that of the 6 million vaccine doses shipped by who to angola in february, one million doses went missing, resulting in shortages to fight the spreading epidemic in dr congo. vaccine and syringes might have been diverted for sale in private markets. in the situation report of 23 september, the who announced a second phase of the vaccination campaign in angola and a planned pre-emptive vaccination campaign for the republic of congo. response to the epidemic in june 2016, a who representative in luanda said that the initial investigation of the outbreak was thrown off course because the first cases in december 2015—the sick eritrean visitors—had what were later identified as fake yellow fever vaccination certificates. all had been to the same restaurant, so food poisoning was initially suspected as the cause of the mystery illness. it was more than a month before blood samples from the eritreans reached the pasteur institute lab and yellow fever was recognized. public health experts identified that as one factor that delayed the response to the outbreak, which came close to being a much larger disaster, if vaccine supplies had not been successfully raised in time, or the disease had spread to other countries and continents. the concurrent zika outbreak drew attention away from a potentially far more serious epidemic of yellow fever.