was 0.11% as of 2020, having declined from a high of 1% when the outbreak first began. Causes and challenges UNICEF and the WHO attributed the outbreak to malnutrition, collapsing sanitation and clean water systems due to the country's ongoing conflict, and the approximately 30,000 local health care workers who had not been paid for almost a year. These factors resulted in a delayed vaccination program, which was not started until more than one million people were already ill. Pre-civil war conditions Even before civil war affected Yemen, it was "beset by circumstances that made it ripe for cholera". A country with high poverty rates, Yemen also suffered frequent droughts and severe water access problems, with only about half of the population having had access to good water and sanitation before the war. Children under five showed a high prevalence of malnutrition, making them further susceptible to disease; Yemen had "one of the highest rates of childhood malnutrition worldwide". The health care system in Yemen before the conflict was weak and lacking infrastructure. For instance, before the war, 70–80% of children were vaccinated against measles, but the vaccination rate had dropped by the end of 2015. Ongoing conflict Because of the ongoing conflict in Yemen, and resulting displacement of people who do not have adequate food, waster, housing or sanitation, pre-existing conditions were exacerbated. Shortages have been made worse by naval and air blockades. Bombing has damaged water and sanitation infrastructure. Airstrikes have destroyed facilities in the country for health care; "half of the nation's hospitals have been either destroyed by Saudi airstrikes, occupied by rebel forces, or shut down because there are no medical personnel to staff them". Doctors Without Borders reported that a Saudi Arabian coalition airstrike hit a new Médecins Sans Frontières cholera treatment center in Abs, in northwestern Yemen. Doctors Without Borders reported that they had provided GPS coordinates to Saudi Arabia on twelve separate occasions, and had received nine written responses confirming receipt of those coordinates. Grant Pritchard, Save the Children's interim country director for Yemen, stated in April 2017, "With the right medicines, these [diseases] are all completely treatable – but the Saudi Arabia-led coalition is stopping them from getting in." Wastewater and solid waste management systems Yemen's wastewater and solid waste management systems are the least developed among Middle Eastern countries, which has been a major contributor to the cholera outbreak. With 16