Introduction
Measles is an acute viral and debilitating illness that can lead to long-term serious complications, including inflammation of the lungs, central nervous system, and brain. In one case out of twenty-five thousand, complications can lead to death; in case of complications on the central nervous system, the consequences can affect health throughout life (Thomas, 2015). However, measles is a well-studied controlled disease; large-scale introduction of vaccination has led to a tangible decrease in the incidence of this infection. Recently, however, measles outbreaks have increasingly begun to be recorded in countries where, it would seem, one step remained before the virus was completely eliminated.
For example, in 2018-2019 Great Britain lost the status of a country without measles; this severe disease is spreading rapidly in the UK (Soucheray, 2019). The return of the incidence of measles requires an in-depth analysis of the causes that led to the new epidemic situation in the country and the role of epidemiology data quality in situation analysis and development of appropriate measures to eliminate the outbreak.
In England (as the administrative and political part of the UK), more than 400 cases of measles were registered in 2018, and already in the first quarter of 2019, 231 cases of measles were clinically confirmed in the UK (Berry et al., 2019), despite the fact that three years earlier this infection in this country was considered as completely eradicated. The worst situation is in London ‑ in May 2018, more than 160 cases were registered in London; over 80 cases were observed in the south-east of the country, while more than 75 were recorded in the central part of the UK (Letley and Ramsay, 2019, para. 4).
Public Health England (PHE) reports that travel to European countries leads to an increase in the number of cases of illness, as well as people’s reluctance to take recommended vaccines (cited in Leong, 2018). The situation in 2018 shows that, in order to stop the measles circulation, the current rate of increase in immunization rates is not enough. The data obtained indicate not only not high immunization coverage at the regional level, but also a record number of cases and deaths from measles.
This means that localization gaps in immunization leave loopholes for the virus. Thus, the current situation represents a serious challenge for epidemiology and determines the need to consider both determinants of the issue and its impact on public health practice, knowledge, and measures taken to stabilize the epidemic situation.
Determinants of the Issue
Speaking about determinants of the measles outbreak under consideration, it should be noted that some attempts are made to explain the problem by the influence of external factors. Many doctors explain the increase in the number of cases with an outbreak of measles in mainland Europe ‑ in Italy and Romania (Principi and Esposito, 2019). However, as the main reason for the rapid spread of measles, some British doctors consider the non-compliance with vaccination standards for children (Principi and Esposito, 2019). According to the rules, children should be given two vaccinations: the first one at the age of one year, and the second before the child goes to school.
However, statistics show that only 87% of British children have been revaccinated, while 95% is considered an indicator that can prevent the spread of measles (Principi and Esposito, 2019). The World Health Organization reports that after reaching this indicator, collective immunity is formed and the spread of the disease becomes unlikely (Said and Al-Balushi, 2019). Thus, to protect against measles, immunization of 95% of the population is recommended (Thomas, 2015).
It is important to understand that success in the fight against measles and other childhood infections in previous years was achieved solely in the implementation of the National Calendar of Preventive Vaccinations. Meanwhile, according to statistics from the UK National Health Service (NHS), only 91.9% of children were vaccinated against measles between 2015 and 2016, compared with 94.2% in 2014-2015 and 94.3% in 2013-2014 (Hungerford, 2017; Keenan et al., 2017). Thus, even a small, at first glance, gap between the “safe” threshold and the actual level of vaccination is potentially the cause of the epidemic situation. The figure below provides statistics on measles in the UK between the beginning of 2012 and the end of 2018.
As can be seen from the graph, after 2013, measles outbreaks occur when vaccination rates have fallen. King College professor Helen Stokes-Lampard reports that one of the reasons for the low vaccination level of the British is the scandal “in the 1990s when, in the article in Lancet, surgeon Andrew Wakefield ‘found’ a link between vaccination against measles, mumps, and rubella (CCP) and occurrence of autism among children.
However, other subsequent studies proved his conclusions to be wrong and ungrounded, and Wakefield was even excluded from the British medical registry” (Mahase, 2019). However, this incident still affected children’s vaccination rates, which could eventually lead to an outbreak of measles.
After reducing the incidence of measles, many began to refuse vaccinations, the misconception of measles as a mild disease played a significant role, while it is known that for every fifteen cases of measles, complications (pneumonia, encephalitis, etc.) occur (Thomas, 2015). It is obvious that, in the minds of healthcare organizers and many people, the opinion has been rooted that a complete, and most important, final victory over measles has been achieved, and you can even raise the question of limiting the principle of mass vaccination or even completely abandoning some vaccines. Unfortunately, the negative attitude towards vaccines has found active support from the media, and “anti-vaccination lobby” has been launched.
As of August 2019, only 87% of British children received a second dose of the vaccine, against the required 95%. So, in Britain, every seventh child did not pass the full stage of immunization. The scores in Scotland, Wales, and Northern Ireland are slightly better than those in England, but also do not reach the target (Soucheray, 2019). The NHS is worried that the mandatory vaccination rate for children in England is at a five-year low. According to Public Health England, among 266 cases occurred between April and June 2019, most were observed in unvaccinated persons of the fifteen and over (Soucheray, 2019).
According to Unicef data, “more than half a million children in the UK were left unprotected against measles between 2010 and 2017 after not being vaccinated against the virus” (More than 500,000 UK children unprotected against measles after missing vaccinations, 2019, para. 1). Among ten most developed and wealthy countries, UK occupies the third place by the indicator of children missing out on their first dose of the measles vaccine (Fig. 2).
Detailed data on measles vaccination status in the UK is presented by Public Health England (Figure 3 below).
The theoretical possibility of eliminating measles is due to the formation of lifelong immunity after an infection, the presence of a single antigenic variant of measles virus worldwide, the absence of reservoirs of measles virus other than humans in the nature, expressed by manifestation indicator of clinical forms of infection, and the presence of effective live vaccines (Thomas, 2015). From the first years of mass measles immunoprophylaxis, a high epidemiological and immunological effect of this measure was noted, which was primarily expressed in a sharp decrease in the incidence and mortality rate (Hungerford, 2017).
Effective evidence-based preventive and anti-epidemic measures led to significant changes in all indicators characterizing the epidemic process, which gave reason to believe that the measles epidemic process in the UK entered the initial phase of elimination of the infection.
However, due to the epidemic situation on measles in the UK in 2018-2019, medical experts believe that the cause of the return of the disease is the spread of misinformation about the measles vaccine, which is why some citizens refuse to vaccinate their children (Public Health England, 2019a).
The Public Health Committee shows the results of parental carelessness and incompetence: while in 2017, 217 children were diagnosed with measles in England, already 913 cases of infection were detected between January and October 2018 (Public Health England, 2019b). Researchers note that if in the pre-vaccination period the features of the epidemic process were mainly due to the action of a biological factor (an infectious agent), then now the influence of the social factor on the epidemic process of measles has increased (Public Health England, 2019a).
Thus, a comparison of the epidemiological data on measles incidence and vaccination for the same period makes it possible to trace the relationship between vaccination and incidence. Data from epidemiological studies allowed revealing that the largest proportion of measles cases occurs in a group of people who are not vaccinated against measles. It has been shown that a decrease of vaccination coverage of only 5% leads to a three-fold increase in the incidence of measles (Mahase, 2019).
That is why experts are unanimous in their opinion that a mere decrease in vaccination coverage could lead to another outbreak of measles. Two decades ago, it seemed that the accumulated collective immunity protects the entire population from a new outbreak, but in recent years, increasingly more parents refuse to vaccinate their children. This situation clearly testifies the necessity to pay close attention to epidemiological data both on the onset of disease and the level of preventive immunization.
Sources of Epidemiological Data: A Critical Evaluation
Obviously, every time we analyse the table or graph presented in the sources of epidemiological information, we must adhere to the following sequence: first, to determine and summarize the facts; then formulate possible explanations; and then decide what additional information is needed to verify this explanation (or for other reasons). At the same time, modelling is a widely used method for evaluating disease control activities. The value of epidemiological models lies in their ability to study hypothetical scenarios and provide the governing bodies with information warning about the possible consequences of a disease and the effectiveness of various control strategies.
In real outbreaks of the disease, the use of the model as an accurate forecasting tool is limited by the complexity and variability inherent in biological systems. However, in the case under consideration, it is possible to trace the relationship between the dynamics of changes in the level of vaccination and the incidence of measles, which determines the high epidemiological value of the data presented by Public Health England.
Countries are declared free from measles if endemic transmission does not occur in a given geographical area for twelve months. The European Regional Control Commission for Measles and Rubella Monitoring (RVC) has determined that for the first time since the beginning of the regional screening process in 2012, the disease is no longer considered to be eradicated in the UK (Soucheray, 2019). Thus, the PHE data allowed making important conclusions about the current epidemiological status of the UK.
Epidemiology of Measles and Public Health Practice and Knowledge
Based on the data on the incidence of measles and on vaccination, the core cause of the outbreak was determined ‑ a drop in the vaccination level. Doctors in the public health system are convinced that the blame is for the subversive activities of “anti-vaccination” proponents sabotaging the national vaccination calendar and spreading unscientific rumours about the terrible consequences of preventive vaccination (Public Health England, 2019b). Myths about the dangers of vaccination represent the main issue that makes parents abandon MMR. Subnational vaccination coverage data also indicate differences within the country.
According to experts from the World Health Organization, most of the arguments of ‘anti-vaccinators’ are not supported by scientific evidence and are described as “alarming and dangerous misconceptions” (Betsch, 2014, p. 17). In 2019, WHO included mistrust of vaccination in the list of ten global threats to public health (Justwan, Carlisle and Carson, 2019). Meanwhile, insufficient coverage by any of the doses of the vaccine creates the prerequisites for transmission of the infection in the future. Thus, there is a clear relationship ‘epidemiological data ‑ taking into account global trends and conclusions ‑ identifying the national situation and specifics ‑ taking the necessary measures.’
Conclusion and Recommendations
The study shows that the main reason for the epidemic distress of measles in the UK is a decrease in the coverage of routine measles immunization, an increase in the number of vaccine refusals. In order to prevent measles outbreaks and achieve its elimination, it is necessary to maintain, at the national and subnational levels, consistently high immunization rates with two doses of the measles component vaccine, as well as identify and eliminate any foci of insufficient immunization of the population.
The government is actively engaged in attempts to manage the situation. To curb the spread of the disease, Prime Minister Boris Johnson called on healthcare leaders to increase the proportion of children receiving a second dose of measles, mumps, and rubella vaccines from 87% to 95% (Public Health England, 2019b). The relevance of attracting a wide range of specialists to immunization campaign increased after the chief epidemiologist PHE announced in April 2019 that “the timing, availability, and location of prescriptions” are more significant barriers to measles, mumps, and rubella vaccines than anti-vaccination messages that affect “a limited minority of parents” (Mahase, 2019, para. 8).
Providing high-quality epidemiological surveillance of the infection is a prerequisite for choosing the optimal measles vaccination prophylaxis. Measles control requires a variety of approaches to ensure timely vaccination of children. In addition, awareness-raising campaigns and activities are needed to raise public awareness of the importance of vaccination and the risks of vaccine-preventable diseases.
Reference List
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