Sydney - Researchers have stressed that major measles outbreaks will likely occur in the wake of the Covid-19 pandemic as early as 2021 due to many missed vaccinations.
Measles is a highly contagious illness caused by a virus that replicates in the nose and throat of an infected child or adult.
The study, published in the journal The Lancet, has called for urgent international action to prevent potentially devastating measles epidemics in the coming years.
"Many children have missed out on measles vaccination this year, making future measles outbreaks inevitable," said study lead author Kim Mulholland from the Murdoch Children's Research Institute in Australia and Chair of the World Health Organization's SAGE Working Group on measles and rubella vaccines.
Mulholland said while 2020 had been a quiet year for measles, in part due to travel reductions and national Covid-19 control measures, the economic impacts would lead to many cases of childhood malnutrition.
Malnutrition worsens the severity of measles, leading to poorer outcomes and more deaths, especially in low- and middle-income countries.
"Children who die from measles are often malnourished, but acute measles pushes many surviving children into malnutrition," he said.
"Malnutrition, along with measles-associated immune suppression, leads to delayed mortality, while co-existing vitamin A deficiency can also lead to measles-associated blindness," he warned.
According to the researcher, the coming months are likely to see increasing numbers of unimmunised children who are susceptible to measles.
Many live in poor, remote communities where health systems are less resilient, and malnutrition and vitamin A deficiency are already increasing.
Professor Mulholland said the Covid-19 pandemic had also had a profound effect on the control of vaccine-preventable diseases, with vaccination campaigns paused in the early months of 2020 and routine immunisation services greatly disrupted in many countries.
The WHO estimates that by the end of October 2020, delayed vaccination campaigns in 26 countries have led to 94 million children missing scheduled measles vaccine doses.
"All these factors create the environment for severe measles outbreaks in 2021, accompanied by increased death rates and the serious consequences of measles that were common decades ago," Mulholland said.
"This is despite the fact that we have a highly cost-effective way to prevent this disease through measles vaccination," he added.
"Without concerted efforts now, it is likely that the coming years will see an increase in measles and its severe, frequently fatal, complications," the study author noted.