In the 2017-2018 school year, the percentage of first graders in Jerusalem who were vaccinated against measles was 96.5%, according to data published by the Health Ministry. In cities with populations over 150,000, the highest rate of vaccination was in Petah Tikva (98.3%), followed by Bnai Brak (97.8%), Netanya (97.6%), Holon and Jerusalem (96.5%). Tel Aviv rated at the bottom of the list of large cities with only 94% of its first graders having been vaccinated against measles. Some of the cities registered a drop in the number of children being vaccinated and as a result, the average for this past year was lower than the previous two years. The cities that saw a drop in the number of vaccinations were Rishon Lezion (-1.5%), Tel Aviv (-1.4%) and Beersheba (-1.2%).Although these rates may seem very high, measles is a highly contagious disease, and while a person infected with influenza will infect on average two other people, a person with measles will infect between 12 and 18 people. In order to prevent an outbreak of the disease, cities must develop “herd immunity,” which requires that at least 17 out of 18 people (94%) be vaccinated. Some sources claim that with measles, the rate is a little lower and so only 90% of the population needs to be vaccinated in order to reach herd immunity. The fact that this percentage is not evenly spread out within a city and some pockets have much lower rates is a major problem, since there are always people who cannot be vaccinated for medical reasons. Thus, it is extremely important to retain high rates so that herd immunity can be reached. Unfortunately, there are 121 communities in Israel where the vaccination rates fall below 94%, such as Safed (89%), Pardess Hanna, Migdal Ha’emek and Tiberias (90%), Eilat and Upper Nazareth (91%), Ramat Hasharon, Tirat Carmel and Arad (93%). The national vaccination average (for communities for which there is data, adjusted for population size) is 96.2%. Of Israeli communities with a population above 20,000, the highest vaccination rate was found in Arab cities, including Kalansuwa (100%), Kafr Kana (99.8%) and Nazareth (99.7%).