Cases of measles-like illnesses have increased over the past few days in Nepal. Among the suspected cases, some were confirmed as measles through laboratory testing. Surprisingly, the current measles outbreak in Kathmandu is being observed in just a four-month interval in the country. This outbreak, thus, can be considered a second attack within a short time this year (2023). The frequency of the measles outbreak in Nepal raises several questions, such as the following: Will there be another measles outbreak very soon? Is the outbreak repeatedly occurring as a post-Covid-19 phenomenon? Was the mass infection caused by reduced vaccine quality or vaccination coverage or inadequate campaigns?

Measles is one of the most transmissible infectious diseases—more rapid than Covid-19 variants. Unvaccinated people are highly susceptible to infection if they come into contact with patients, especially those who are sneezing, coughing or talking. Symptoms begin 10-14 days after exposure to the infection. High-grade fever, red eyes, watery eyes, runny nose, cough and small white spots inside the cheeks are the major signs and symptoms of measles. However, during this phase, many patients do not visit health care centres, believing it to be a common cold, and practice self-medication.

Patients only go to hospitals after the rashes begin to spread to other parts of the body. Rashes are usually seen approximately after 14 days of exposure and can be transmitted to others four days prior to the onset of symptoms. This means that once a measles outbreak occurs, it will be difficult to break its chain in the community. Complications include pneumonia, encephalitis, blindness, ear infection, and severe diarrhoea.

Measles is usually diagnosed based on clinical symptoms, rash and evidence of an ongoing outbreak. However, measles symptoms overlap with many other infectious diseases; thus, laboratory confirmation is necessary. Recently, the Government of Nepal confirmed signs of the virus among patients in Kathmandu. This outbreak raises questions about the effectiveness of the “Urban Childhood Immunisation Programme” and its campaign in Nepal. One possible reason could be not receiving vaccines due to a fear of Covid-19.

It was found that most of the children in Nepalgunj who showed signs of measles were unvaccinated or had received incomplete vaccination doses. This means that the frequent outbreaks of measles recently seen in Nepal have to do with the reduced vaccination coverage. However, we failed to address this issue, which resulted in a second wave of measles outbreaks immediately after the first in Kathmandu.

Recently, the World Health Organization warned that despite the availability of a safe and cost-effective vaccine, measles cases increased significantly in 2022 (904 cases from 27 countries) compared to 2021 (159 cases from 22 countries) worldwide. Moreover, European countries (17 countries reported from the WHO European region) have also witnessed a significant increase in measles cases since the start of 2023.

This shows that the measles outbreak is becoming a grave concern globally. The outbreak has also coincided with the Covid-19 pandemic that began in early 2020. Whether this re-emergence of measles outbreaks is due to reduced vaccination coverage or due to the Covid-19 impact can be an important issue for future research.

A study conducted in Chandigarh, India, in 2019 showed that many children aged 5 to 10 years lacked protective immunity against measles (60 percent). It showed community-based baseline data on measles in India. However, Nepal lacks sufficient and similar baseline data on the long-term protective level of antibodies against measles in vaccinated individuals. I had made observations of measles disease in adult groups, especially prior to the Covid-19 waves in Nepal.

This showed a requirement of an additional dose even after completing the compulsory two-dose vaccine as per the government’s protocol. This need, however, requires further studies for when (at what age) and how many additional doses may be required. Several local Newspapers and online news portals have reported that many older age groups also showed symptoms similar to measles in Kathmandu, meaning measles is spreading explosively not only in children but also in adult groups.

Another reason for the vaccine failure is due to the poor vaccine delivery system, especially in remote areas and the lack of cold chain maintenance. Some studies have shown that failure in maintaining vaccines during delivery (e.g., transportation) and storage cold chain resulted in a decrease in the potency of the measles vaccine. In other words, vaccines may not produce the protective level of antibodies required against measles. At present, it is unknown whether the lack of cold-chain maintenance, as per manufacturers' guidelines, is a reason behind the current outbreak in Kathmandu.

Besides vaccination, prompt intervention from the concerned body and the public is critical to stop further spread of the virus in the community. For example, if a child shows symptoms similar to measles, parents must first inform their school and isolate them for at least four days after the rash erupts. Those who have had close contact with suspected cases can get vaccinated within 72 hours following exposure, which can greatly help reduce the risk of developing severe measles disease and or complications. It is necessary to close schools or colleges in the area to prevent the spread of the virus.

To sum up, while Nepal had committed to eliminating measles by the year 2023, the repeated measles outbreaks seen across the country have been preventing the country from achieving its goal. Most importantly, if the measles outbreak is spreading in Nepal due to poor vaccination coverage, then the outbreaks of other serious infectious diseases, such as polio, Japanese encephalitis, rubella, whooping cough and diphtheria cannot be ruled out in coming years.