Vaccination against serious diseases has saved countless lives around the world. Each year, immunisation drives protect against life-threatening diseases such as measles, polio, diphtheria and tuberculosis.
But while global vaccine coverage has markedly increased over time, issues of access, equity and uptake continue to be a significant challenge, particularly in low-income countries.
The COVID-19 pandemic has brought these issues into sharper focus, including growing awareness of the need to understand the factors that may support or inhibit people from being vaccinated.
Barriers to vaccination are multiple, complex and context-specific, according to Dr Kerrie Wiley, a Research Fellow with the School of Public Health, who studies the social and behavioural aspects of immunisation.
“Some people might want the vaccine but aren’t able to get it because the clinic isn’t open, there’s no form of transport, or a whole range of practical issues. Then there’s factors such as the social sphere and whether your family is vaccinated, what your friends are doing, whether you’ve been recommended to have a vaccine by a healthcare worker,” Dr Wiley said.
“There’s also people who may be worried about the vaccine, or don’t trust the health department, don’t trust the government in some settings, or may have read something on the internet. This is very specific to the context, very specific to the country or the culture, and quite often specific to the vaccine as well.”
When it comes to delivering pandemic vaccines, the capacity of health systems to deliver doses is also a key factor, says Associate Professor Meru Sheel, an infectious diseases epidemiologist with expertise in vaccine design and immunisation in the Asia-Pacific region. Many countries, while accustomed to delivering childhood immunisation, are vaccinating adults on a large scale for the first time.
“Particularly in low- and middle-income countries, where health systems have been stretched beyond capacity, there is already a workforce and training shortage, healthcare workers need to be rapidly skilled up, cold chain systems managed and information systems established to monitor the effects of the vaccine. The COVID-19 vaccines are also a new and evolving domain, and the knowledge changes every day, requiring regular policy updates based on the local epidemiology,” she said.
“When vaccinating the whole population, extra resources need to be invested, so the health system has to be adaptable and expandable. Not all health systems can expand at the necessary rate and scale.”
In Southeast Asia, challenges of geography, population size, capacity and resources are among the practical issues each country has grappled with in rolling out COVID-19 vaccines.
Indonesia and the Philippines, for example, face logistical challenges associated with being vast archipelago nations. In Myanmar, where a military coup in February 2021 triggered a political, economic and humanitarian crisis, access to health services has been severely disrupted.
According to Our World in Data, as of 24 April 2022, Brunei and Singapore had the highest proportion of their populations fully vaccinated (both over 90 per cent), followed by Cambodia (84 per cent), Malaysia (81 per cent) and Vietnam (79 per cent). Indonesia, Timor-Leste and Myanmar lag much further behind.
Dr Thu Anh Nguyen is an infectious diseases and public health researcher in the Faculty of Medicine and Health, who is currently based in Vietnam.
She points out that, as with many countries in 2021, Vietnam initially struggled to access enough supplies of vaccine. But the main issue has now moved from one of access to uptake.
“With Omicron now the dominant variant, and reports suggesting it causes more mild disease, people are not as concerned and think they don’t need a third vaccine dose. At the same time, information and rumours have circulated about adverse reactions to the vaccine, and some people no longer want to have it,” Dr Nguyen said.
“The next issue for Vietnam is targeting children under 12 for vaccination, including for other diseases. During the severe COVID-19 outbreak last year, when stringent government measures were in place, many people couldn’t access vaccination centres and a lot of children were delayed in receiving vaccines.”
There have been huge disruptions to routine immunisation in the region and across the world – most countries have had at least one vaccine campaign disrupted.
Even as some countries in Southeast Asia achieve high vaccination rates for COVID-19, immunisation for other diseases in some cases has stalled.
“There have been huge disruptions to routine immunisation in the region and across the world – most countries have had at least one vaccine campaign disrupted. There has been an increase in what we call ‘zero-dose children,’ that is infants who receive no routine vaccinations,” said Associate Professor Sheel.
“We anticipate that there will be an increase in outbreaks of vaccine preventable diseases, such as measles and diphtheria, which are respiratory viruses that can lead to big outbreaks.”
According to the World Health Organization’s latest global pulse survey, disruptions to health care, from emergency care to elective surgeries, have been reported in countries of all income levels due to the pandemic. Almost half of 82 countries surveyed reported disruptions to routine immunisation services.
A lack of resources; intentional service delivery modifications, such as temporary closures of clinics; and health worker availability were among the challenges that countries reported.
In Indonesia, which experienced a significant spike in COVID-19 cases and deaths last year, restrictions impacted access to key health services, including immunisation.
“The number of children not receiving their first dose of diphtheria, tetanus and pertussis vaccine has really risen, and so there’s significant challenges in coverage rates,” said Madeleine Randell, a PhD candidate in the School of Public Health who is researching the health system in Aceh, Indonesia.
“In August 2021, the Indonesian Ministry of Health reported there had been a 74 per cent decrease in demand for routine immunisation because caregivers were afraid of getting COVID-19, which is of course a legitimate fear.”
The need to re-establish essential immunisation programs around the world is an emphasis of this year’s World Immunization Week, which runs 24-30 April.
Ms Randell is among a team of researchers from the University of Sydney, University of Indonesia and the Murdoch Children’s Research Institute working to examine perceptions and demand for routine immunisation services in two provinces of Indonesia. The UNICEF-funded study is being led by Professor Julie Leask, and includes Associate Professor Sheel and Dr Wiley.
The project, which has surveyed participants in both urban and rural areas of Central Java and West Nusa Tenggara, aims in part to understand how the COVID-19 pandemic has disrupted routine immunisation and other maternal and child health services, with a view to informing policy and service strategies.
“A real strength of the study is that it draws on the World Health Organization’s Behavioural and Social Drivers of Vaccination (BeSD) framework, that focuses on major drivers affecting vaccine uptake across four domains: what people think and feel; social processes, such as family and community influences; motivation; and practical issues, such as ease of access,” said Ms Randell.
“We’re hoping that the end results will be shared widely with health stakeholders across Indonesia to really help inform planning and ensure effective access to high-quality immunisation services and other maternal and child health services,” she said.
“It’s important to understand those social and behavioural drivers of vaccination. If we can see where the issues are, you can then start to build more effective strategies to actually improve vaccine uptake.”
The success of immunisations has always been limited by issues of public acceptance. Listen to SSEAC Stories with Dr Kerrie Wiley, who unpacks some of the factors as to why people are or aren’t vaccinated.