Abstract
Despite an effective vaccine, the goal of measles elimination has remained elusive so far. Our study found that almost one-third of children with measles were less than 9 months of age, which suggests the need for strengthening routine immunisation along with adolescent vaccination.
Introduction
Measles is a highly infectious virus-borne illness posing risks of severe complications, especially in infants, malnourished and immunocompromised children, with a primary case reproduction number (i.e., the average number of secondary cases per case patient) of 12–18. 1 It continues to remain an important cause of death among young children globally and can also lead to serious adverse outcomes such as blindness, pneumonia and encephalitis. 1 Before the introduction of the measles vaccine in 1963, major epidemics occurred every 2–3 years, causing an estimated 2.6 million deaths each year. However, despite a safe and cost-effective vaccine, an estimated 107,500 people died from measles in 2023 – mostly children under the age of five years. 2
There has been an unrelenting upsurge in measles deaths from 2016 to 2018, suggesting that the existing strategies need drastic improvement to achieve the goal of measles elimination. 3 The COVID-19 pandemic further increased the risk of measles outbreaks, with millions of doses of measles-containing vaccines being postponed or missed. 4 Since 2024, all World Health Organization (WHO) regions have reported an increased number of measles cases, with 395,521 laboratory-confirmed measles cases in 2024 and 16,147 reported during the first two months of 2025, with almost half the reported cases being hospitalised. 1 India has one of the highest numbers of measles cases in the world, thus putting the goal of eliminating measles in jeopardy for the nation.4,5
Measles is a highly infectious disease with an effective vaccine. This retrospective study was done to describe the clinical and epidemiological characteristics of children diagnosed with measles at a tertiary hospital in North India. The large number of young infants affected emphasises the need for adolescent and adult immunisation to ensure long-lasting immunity if we want to achieve the goal of measles elimination.
Materials and methods
Our retrospective study was conducted in the Department of Paediatrics of a tertiary hospital located in North India on children aged 0–18 years, fulfilling the WHO definition of measles from December 2022 to May 2023. Children were further classified according to the WHO definition of laboratory-confirmed, epidemiologically linked, and clinically compatible measles cases. 6 These are defined first as a suspected case confirmed positive by testing in a proficient laboratory with vaccine-associated illness ruled out; second as a clinical case of measles not confirmed by a laboratory but geographically and temporally related, with dates of rash onset occurring 7–21 days apart from a laboratory-confirmed case or another epidemiologically linked measles case; and third as a clinically compatible measles case as one with no adequate clinical specimen taken and no link epidemiologically to a laboratory-confirmed or epidemiologically linked case of measles or other communicable disease.
Hospital records of included children were reviewed to evaluate the clinico-demographic profile, vaccination history, and outcome (discharge or death). Abnormal laboratory parameters were defined as total leucocyte count <4 × 109/L or >12 × 109/L, platelet count <15 × 109/L, alanine transaminase >45 IU/mL, aspartate aminotransferase >60 IU/mL in children <3 years and >50 IU/mL in children <3 years, albumin <35 g/L, INR >1.5 and haemoglobin <80 g/L. No children were excluded from the study. The study was approved by the ethical committee of our institute.
Data were collected and analysed using SPSS version 24.0. A descriptive analysis was done by calculating frequency, mean (standard deviation [SD]) and median (interquartile range [IQR]) for continuous variables and proportions for categorical variables. The correlation between clinical and laboratory parameters with outcome was assessed using the Spearman correlation coefficient. A p-value of <0.05 was considered significant.
Results
A total of 81 children were classified as cases of measles, of whom 70 (86.4%) were laboratory-confirmed, 4 (4.93%) epidemiologically linked, and 7 (8.64%) clinically compatible measles. Of the 81 confirmed cases, 56 (69.13%) were males, and the median age was 12 months (IQR: 3.25). Some 26 (32.1%) children were <9 months of age, and 12 (14.8%) were >5 years. Of the children who were eligible for vaccination, 39 (48.1%) did not receive even a single dose of vaccine, while 16 received only one dose. A total of 72 (88.8%) children were hospitalised, with 22 (30.9%) being <9 months and 15 (21.1%) between the ages of 5 and 18 years. No children had severe acute malnutrition. Laboratory parameters are shown in Table 1. There was no significant difference in the clinical presentation and laboratory parameters among infants and toddlers.
Laboratory parameters of children with measles.
Values expressed as mean (SD)
aMedian (IQR).
All had fever and rash, and 86.4% had a cough. The mean duration of hospital stay was 6.1 days. The most common complication was pneumonia (49.3%), followed by diarrhoea (28.4%), conjunctivitis (24.7%), meningitis (2.5%), and acute otitis media (1.2%). There was a significant association between respiratory distress (p = 0.041), oxygen requirement (p = 0.044), and immunisation status. There was no mortality in our study cases.
Discussion
Measles is a highly contagious disease with phenomenal transmissibility and thus has a potential for vast international spread.3,7 The clinical profile was similar to that reported in other studies.8,9
Despite intensified campaigns enhancing measles vaccination, such as Intensified Mission Indradhanush 5.0, the goal of measles elimination still remains far away. We observed measles in significant numbers of infants aged <9 months, which is the recommended age of the first dose of measles vaccine in our country, possibly owing to the early waning of maternal antibodies after vaccination. 8 The recommended age for the first dose of measles-containing vaccine depends on the waning of maternal antibodies and the risk of measles exposure. 10 In countries where measles is virtually eliminated, the first dose may be given at 12–18 months of age for maximum immunogenicity, although this schedule leaves younger children susceptible to infection. In countries where measles is endemic, mainly low- and middle-income countries (LMICs), the first dose of measles vaccine is usually given at 9 months of age. Recent data have also shown an increasing rate of decline of maternal antibodies both in measles endemic regions and in areas where measles has been eliminated. A meta-analysis of data from LMICs (2018–2024) also showed that by 4 months of age, only 24–35% of children remained seropositive. Young infants are also at a heightened risk of severe measles-related complications such as pneumonia, encephalitis, and death. Determining an appropriate timing of an early dose vaccine requires a balance between the age-stratified infection risk and the duration of vaccine effectiveness over time. An early dose of measles vaccine in children <6 months old may be considered in outbreaks of measles. 1
A large proportion of older children had also received a single vaccine, emphasising the need for additional vaccination. Adolescent vaccination may play a key role in the elimination of measles apart from strengthening the existing immunisation practices. Massive and frequent supplementary immunisation actions are also recommended amongst the targeted age groups of 9 months to 15 years to ensure almost 100% coverage against measles and rubella. The WHO also recommends that each country should build its own evidence base to determine age-specific immunity gaps and determine the target age range for measles and measles-rubella campaigns.
Therefore, a paradigm shift in the approach of measles immunisation is needed to reach the evasive target of measles elimination. Suggested strategies are vaccine coverage, supplementary immunisation action, adolescent vaccination, robust measles surveillance, and targeting vaccine hesitancy with effective communication.11,12
Our study was a retrospective, single-centre, hospital-based study with a small sample size, which thus potentially limits the applicability of our study. However, we aim to highlight the need for further studies to look at the emerging trends of measles and the need for intensive measures to achieve the goal of measles elimination.
Footnotes
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
