Measles outbreaks, a public health focus of the question.
Juan Gérvas, retired general practitioner, Equipo CESCA, Madrid, Spain. jjgervas@gmail.com @JuanGrvas
We have problems with measles. But the key question is not the acceptance of the vaccine, but access to it and problems with its effectiveness.
1.- Access
For example, in America measles outbreaks have relationship with access problems to the vaccine for the poor and indigenous people (in 2018, Brazil, Amazonas 9,778 cases and 6 deaths, and Venezuela 5,668 cases and 74 deaths) (1).
In Europe, measles outbreaks have also relationship with access to the vaccine in situations of social disorganization, poverty and ethnic minorities, such as gypsies. In 2018, for almost 900 millions populations, there were 82,596 cases and 72 deaths. As the WHO Europe pointed out: “Most of the countries struggling with suboptimal immunization coverage against measles in the Region are middle-income countries” and the fists measure to close the door on measles is: “to ensure that all population groups have equitable access to vaccination services and that these are convenient” (2).
2.- Effectiveness
The measles vaccine produces immunity that fades after some years. There is a continuous waning of vaccine-induced immunity (3, 4, 5). For this reason, in New Zealand has being calculated that additional immunisation beyond childhood programs to target naïve individuals is economically beneficial even when childhood immunisation rates are high (6).
Therefore, when the largest outbreak of measles in North America (Canada) was studied, almost half of those affected were properly vaccinated (7). In an outbreak in Porto, in 2018, of the 96 confirmed cases, 67 (69.8%) were vaccinated with two doses of measles vaccine or measles mumps and rubella vaccine (8).
Viruses evolve which might also decreases the effectiveness of the vaccine. Virus exhibit different antigenicity and it has been hypothesized that this could potentially lead to less efficiency of the current vaccine or cause genotypic-specific escape to neutralization (9).
3.- Outbreaks with more than 95% vaccine coverage
In Spain, vaccination is voluntary but coverage is over 95%. This does not prevent outbreaks of measles, as in Madrid in 2011, with measles virus antibodies of 97.8% in the population (10). In this outbreak of measles, the gypsies were 36% of those affected being only 1% of the population (11). In the largest outbreak in Spain, in Seville in 2011, there were 1,760 cases in a poor and marginalized population (12).
4.- Confidence and trust
On the other hand, the case of the Philippines measles outbreak is exemplary in terms of the necessary care that must be provided throughout the field of vaccines. The errors in the vaccination against dengue have discredited the authorities, and the vaccines, and we should see the rejection of them, the outbreak of measles and the consequent deaths as "side effects" of such errors (13, 14).
Summary
The scenario in measles epidemiology is changing (9) and the analysis of measles outbreaks should to go far beyond the "anti-vax", the mandatory policies and the discredited study published in The Lancet in 1998 (Wakefield and autism).
We need to take into account problems of access as demonstrate the outbreak in Madagascar (15), acceptability and a mix of both (16, 17) and problems of effectiveness. Restauring confidence and commitment is not enough.

References
1.- PAHO. Epidemiological Update. Measles 18 January 2019. https://www.paho.org/hq/i...
2.- WHO. Measles in Europe: record number of both sick and immunized. http://www.euro.who.int/e...
3.- Kremer JR et al. Waning antibodies in measles and rubella vaccinees—a longitudinal study. https://www.sciencedirect...
4.- Glass K, Grenfell BT. Waning immunity and subclinical measles infections in England. https://www.sciencedirect...
5.- Davidkin I et al. Persistence of Measles, Mumps, and Rubella Antibodies in an MMR-Vaccinated Cohort: A 20-Year Follow-up. https://academic.oup.com/...
6.- Hayman DTD et al. Cost-benefit analyses of supplementary measles immunisation in the highly immunized population of New Zealand. https://www.sciencedirect...
7.- Machado R et al. Measles outbreak in a tertiary level hospital, Porto, Portugal, 2018: challenges in the post-elimination era . https://www.eurosurveilla...
8.- Serres G et al. Largest Measles Epidemic in North America in a Decade—Quebec, Canada, 2011: Contribution of Susceptibility, Serendipity, and Superspreading Events. https://academic.oup.com/...
9.- Tramuto F et al. Case-based surveillance of measles in Sicily during 2012-2017: The changing molecular epidemiology and implications for vaccine strategies. https://journals.plos.org...
10.- García-Comas L et al. Seroprevalence of measles and rubella virus antibodies in the population of the Community of Madrid, 2008–2009. https://www.sciencedirect...
11.- García-Comas L et al. Community-wide measles outbreak in theRegion of Madrid, Spain, 10 years after theimplementation of the Elimination Plan,2011–2012.
https://www.ncbi.nlm.nih....
12.- Montaño Remacha C et al. [Outbreaks of Measles in Andalusia, Spain, during the Period 2010-2015]. http://scielo.isciii.es/s...
13.- Smith N. Philippines immunisation rates plummet amid Dengue vaccination scare. https://www.telegraph.co....
14.- BBC News. Measles outbreak declared in Philippines. https://www.bbc.com/news/...
15.- WHO. Measles – Madagascar. https://www.who.int/csr/d...
16.- Muscat M. Who Gets Measles in Europe? https://academic.oup.com/...
17.- Danchin M et Kaufman J. Building vaccine confidence: more information is not enough. https://insightplus.mja.c...
18.- Turner R. Measles vaccination: A matter of confidence and commitment. https://journals.plos.org...