Recently there has been increasing concern about the number of measles cases occurring. Some experts have suggested it may be necessary to address surges in diseases like measles, alongside falling rates of immunisation. Measles can be unpleasant but will usually pass in about 7 to 10 days without causing any further problems. However, it can lead to very rare but serious and potentially life-threatening complications in some people. These include infections of the lungs (pneumonia) and brain (encephalitis).
The uptake of the MMR (Measles, Mumps and Rubella) vaccine has been declining in many countries. The reason is not clear. Rates dipped in the 1990s following publication of a report linking MMR to autism, but partly recovered after that research was discredited and disproved (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136032/). The volume of anti-vaccine sentiment on social media has been growing and experts have warned that 'vaccination deniers' are gaining traction online.
Arguments against compulsory vaccination include: adverse reactions do occur, though they are rare; it is not necessary to achieve 100% immunisation rates to achieve herd immunity; and compulsory vaccination breaches the fundamental human right of a parent to choose what happens to their child.
Nevertheless, it has been suggested that the risks from measles outbreaks are now so high that unvaccinated children might expose others to unnecessary risk when attending school, and that they should therefore not be allowed to attend (https://link.springer.com/article/10.1007/s10730-013-9221-5),(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8569289/), (https://www.verywellhealth.com/who-is-at-risk-from-unvaccinated-kids-2634420).