While on the topic of my activity using the WHO database, I will relate this to the recent measles outbreak in the U.S. Based on this article, “herd immunity” kicks in at about 92-94%. Shockingly, some counties of California have immunization rates is as low as 18-23%. Evidently, some people in these counties feel they can “afford” to refuse vaccination because of their access to first rate medical care in the event that their children are stricken. This is not the case in Africa, where childhood measles is often a matter of life and death. While politicians debate the right of parents to refuse vaccination for their children in public schools, thanks to the WHO, you do not need to be an expert to compile raw data showing the effectiveness of this policy in regions like Africa. The graph below is based on the same lab activity I described on the previous post (2-5: Risk Factors and Health Outcomes in Africa). Each dot represents a country in Africa and mortality rates are limited to children up to five years old: