Introduction
The article “Autism Occurrence by MMR Vaccine Status Among US Children with Older Siblings With and Without Autism” by Jain, Marshall, Buikema, Bancroft, Kelly, and Newschaffer (2015) will be critically analyzed in this report. The research problem of the study, clearly stated by the authors, is to examine the widespread belief that the measles-mumps-rubella (MMR) vaccine is linked to instances of children having autism spectrum disorders (ASD), causing lower vaccination levels, particularly if a sibling already has ASD. The issue is significant to nursing since disinformation about vaccines is causing a persistent drop in immunization rates of children during the recommended time frame. Furthermore, this unproven link with ASD is leading more parents whose older children already have the condition to be wary of immunizing their younger kids. As a result, this creates a nursing issue of patients being misinformed and a population health concern of lowered herd immunity for these serious diseases. Therefore, this study is justified as the authors note that MMR vaccination has declined by 20% in families where an older child has ASD and younger siblings are unlikely to have the full MMR immunization.
There are no objectives stated, but the study set an objective to determine ASD occurrence based on the MMR vaccine status in a large sample of US children with older siblings who may or may not have ASD. There is no theoretical or much of a conceptual framework present in the study. The authors offer a brief background on MMR vaccinations and the public perspective of its link to ASD which causes a drop in immunizations, particularly if older siblings have been diagnosed. This is the only connection between the literature and the research purpose. There is no inherent reasoning, theoretical, or conceptual framework provided. There is no dedicated literature review, with all the information being present in the introductory section. Examining the cited sources, the literature, for the most part, is within 10 years of the 2015 publication date, with a minority of sources published in the early 2000s. The organization of information in the text follows a logical format by introducing the background for the vaccine, incorporating the issue of ASD connection, and leading up to the primary research question.
Methods
The implemented design was a retrospective cohort study that used an administrative claims database that includes health claims data for more than 30 million diverse individuals, with enrollees distributed by geographical area, age, and sex. The design is fitting with the purpose of the study to examine statistical population trends on a large scale. This type of design allows to gather and analyze a large amount of historical health data. It is linked to the sampling method by sampling a group of people who have a common exposure factor, which is the MMR vaccine, and a sibling with an ADS and compare it to a group receiving the MMR vaccine which did not have a sibling with ADS. The statistical analysis is relatable since the longitudinal design helps to determine the influence on the incidence of a condition and can be used to draw conclusions about multiple outcomes or rare diseases, although some key statistics and bias controls may be missing.
The sample consisted of 95,727 children, practically equally divided in gender. Birth years were distributed equally ranging from 2001 to 2007. The sample was also proportionally representative of the US regions and racial demographic distribution in the United States. The sample is well outlined in the study, both descriptively and in terms of numerical percentages. The sampling procedure is described in detail as it consisted of searching the database for children born between 2001 and 2007 who were enrolled in health insurance as well as a sibling enrolled for at least 6 months in the period between 1997 and 2012. The authors do not justify the size of the sample other than mentioning that they are required to conduct a large-scale study to verify whether any correlation exists between MMR immunization and ASD.
The study protocol was to develop an algorithm was developed to isolate the MMR vaccine receipt (exposure based on doses and age) as well as ASD status in indexed children and their siblings. Based on the recommended age for each MMR dose, relative risks were estimated and adjusted to compare ASD status. Time-varying and fixed covariates were included to avoid confounding factors, and each child’s overall health status was indexed under a modified version of the childhood chronic conditions (CCC) score. The study protocol was not clear as it was not identified and mixed in with other descriptions of methodology and populations.
The primary instrument used was a claims-based algorithm that was able to identify 2 or more claims on separate dates using the International Classification of Disease (ICD-9-CM). No other clear instruments of measurement were described. The claims-based algorithm did measure the concept necessary – the relative risks for children, as it was designed to use specifically for these types of studies. The authors comment on its reliability, that the algorithm has an 87% accuracy (Jain et al., 2015).
The author does not explicitly address validity threats, but the use of ICD procedure codes and nationally recommended vaccine dosages can be considered measures to ensure validity. The authors state that the New England Institutional Review Board reviewed the experiment and waived the need for informed consent since the study is based on existing public and de-identified data. Human subjects were never contacted or reviewed beyond the available statistical data. There seem to be no evident ethical concerns since data was anonymous in terms of names, but only provided basic demographic information and it was approved by a review board. The detail in the study provides enough information to replicate it, but some elements regarding the algorithm used and more nuanced characteristics may need to be confirmed with the authors.
Results
The sample characteristics are described in significant detail, offering their date of birth, sex, geographic region, race, household income, parental education level, potential health problems, as well as the presence of a sibling with ASD or not. Since there was no direct hypothesis, and the research question was to confirm an existing knowledge for the scientific community, they were answered as one, stating that there is no direct link between the MMR vaccine and ASD. The data collected was mostly quantitative, particularly the presence of MMR vaccinations, diagnosed ASD, and relative risks determined by the algorithm, as well as basic demographic data. The researchers used a variety of data analysis techniques such as statistical analysis and statistical significance testing through Yates X2 test, Wald X2 statistics, and Cox proportional hazards models. The analysis was performed using SAS statistical software.
Tables are presented in the study to supplement the text. One table is a general overview of the characteristics of the study sample, breaking down everything by numbers and percentages, having two distinct columns of older siblings with and without ASD. The second table offers unadjusted and adjustive relative risk estimates of MMR vaccination and ASD, divided by age and dosage of the vaccine. Each table offers footnote explanations and can be easily understood, helping to understand the study results. Some data from the tables is repeated in the text, but the table offers a more in-depth analysis of the information. In brief, the findings indicate that the MMR vaccine does not increase relative ASD risk in either of the two doses or the presence of a sibling with ASD. The authors performed the careful statistical analysis and quantitative bias analysis, presenting both adjusted and unadjusted data, showing no statistically significant link between the conditions and overwhelming support for the medical community that vaccinations are safe.
Implications for Practice
The authors directly relate the findings to the research question, indicating that there is no demonstrated association between the MMR vaccine in any dosage and ASD risk in children, even if they had a sibling with the condition. In fact, the prevalence of the ASD diagnosis leads to a group of children who are under-vaccinated, which is on par with the previous assumptions that selective parental decisions to delay or avoid MMR immunization if they notice social or communication delays.
The authors note that the findings and conclusions are similar to those of previous studies conducted on the research question. When discussing the results and findings, there are several times that the authors refer that the data is “consistent with studies in other populations” (Jain et al., 2015, p. 1538). Therefore, while there is no discussion regarding how this research conflicts with other studies, there is some attempt to compare and contrast with similar research in the field but with other types of populations, thus demonstrating certain patterns. The researchers note only one limitation to the study which is that the data was collected from an administrative claims database in the United States, which only includes privately insured children.
The authors state that diagnoses and procedures which are not generated for payment or data for uninsured children are likely underreported, which is highlighted to be a limitation to the generalizability of the study’s findings. However, some cases may be overreported as well and children that are considered unvaccinated may have received immunizations in other settings such as schools and public health clinics. Another evident limitation includes a lack of a theoretical or conceptual framework to the study or a greater exploration of the psychological and social reasons why there is a widespread belief about the risk of ADS linked to the MMR vaccine. These are all elements to consider in future research on the topic as well as nursing practice when conducting public health interventions.
The study did not present any new knowledge that the scientific and medical community was unaware of beforehand, but it confirmed that there is no link between ASD and MMR immunizations in children, whether or not their siblings shared the condition. The MMR vaccine is not harmful, even for kids that are at a higher hereditary risk for ADS. However, the study was the first to examine such a large sample of children and data to address the growing social concerns of parents with ADS. The authors do not directly state any implications for practice, but these can be implied by medical professionals in the field of public health as well as practitioners who work with concerned parents on a daily basis. A large-scale study such as this can contribute significantly to interaction with parents and patient education on the importance and safety of vaccinations. If the data is used in public health promotions, it may be beneficial towards creating a more pro-vaccine environment among parents and encourage medical organizations as well as other influential public entities to support immunization efforts.
Overall Presentation and Summary
The overall presentation is well-done. The title is direct in emphasizing the study research question, population, and included variables of MMR vaccination and ASD. While there is no explicit mention that this is a quantitative study, the word “occurrence” indicates that prevalence is most likely to be measured which is a numerical indicator. The abstract consists of a shortened breakdown of the study by sections as typical for professional and medical studies. It included indicating the topic, objective, setting and sample, methods and measures, results, and conclusions. Therefore, it can be said that the abstract very accurately and thoroughly represents the contents of the study.
The report demonstrates logical consistency by following a structured method of presenting information, methods, and findings. The scientific method and the flow of the author’s arguments and supporting evidence can be easily followed. The writing in this study is clear and precise, both in style and content, making it comprehensible to follow even for readers without any type of medical education. In conclusion, the article was a successful attempt to study and address a very critical topic regarding vaccinations which is important for population health. While there were some limitations, the study did well in its validity and presentation, offering a foundation for future research in the field.
Reference
Jain, A., Marshall, J., Buikema, A., Bancroft, T., Kelly, J. P., & Newschaffer, C. J. (2015). Autism occurrence by MMR vaccine status among US children with older siblings with and without autism. JAMA, 313(15), 1534-1540. Web.