World Immunization Week 2024

Humanly Possible: Immunization for All

The theme for World Immunization Week 2024 is in celebration of 50 years of the Essential Programme on Immunization (EPI)

Every year, in late April, World Immunization Week is observed. It aims to educate about why vaccines are needed to protect the health of billions around the world from communicable and vaccine-preventable diseases. To underscore the importance that vaccinations play in saving lives, the global public health campaign lasts seven days, from 24-30 April.

The Impact of EPI:

Vaccines have emerged as a cornerstone of public health, preventing the spread of deadly diseases and saving lives

- World Health Organization (WHO)

This year World Immunization Week celebrates the 50th anniversary of the Expanded Programme on Immunization (EPI) [1]. According to the WHO [19], when it started in 1974, the EPI’s mission was to immunise all children, everywhere, against:

diphtheria
measles
polio
tetanus
pertussis (whopping cough)
smallpox

The programme’s success is evident in the momentous achievement of smallpox eradication in 1980 [22].

Five decades on, the E in EPI has been changed to Essential and its goals expanded. Along with upholding universal access to relevant vaccinations and strengthening current immunisations programmes, the EPI aims to ensure the supply and delivery of vaccines not just to babies and young children, but all children, adolescents and adults [1]. The WHO’s EPI is a key component of both the pandemic prevention, preparedness and response accord and UN Sustainable Development Goals (SDGs) target 3.8 Universal Health Coverage by 2030 [44].

The creation in 2000 of the Global Health Partnership, Gavi, the Vaccine Alliance, added another dimension to EPI’s success [24]. By offering countries the help and support needed to introduce a broader range of new vaccines like, Hib, Pneumococcus, rotavirus, HPV, meningitis A, malaria, and Japanese encephalitis, Gavi has significantly increased the range of immunity and protection against a wider spectrum of diseases [1].

Immunisation represents one of the most effective and cost-saving public health interventions. For example, a dose of the MMR vaccine which protects against 3 diseases costs only US$1.14 [25]. But, for numerous reasons, adults and children miss out on essential vaccines [26]. Growing conflicts, economic downturns, and a rise in vaccine hesitancy are some of the global threats to prevention efforts [27]. Added to this, are also growing challenges in gaining access to vaccines [28]. As a result of these factors, the world is seeing sudden outbreaks of diseases like diphtheria and measles that, until now, had nearly been eradicated [2].

The COVID-19 pandemic has been a disaster for childhood immunization... in just three years, the world has lost more than a decade of progress.

- The State of the World’s Children report, unicef 2023

Decades after it was declared eliminated in Europe and the Americas, there have been increasing outbreaks of measles across all three continents in the last few years [25, 29, 30]. Furthermore, recently there has been an increase in cases of the 100-day-cough (pertussis or whooping cough) across the United Kingdom [12]. Moreover, the Africa CDC states in 2023 there were Diphtheria outbreaks in multiple countries across the continent [31]. These outbreaks, underscore how essential the routine immunisation schedule is to fend off these threats.

This special feature blog highlights why making it humanly possible to have immunisation for all is so vitally important because immunisation has been proven to save lives [23]

Vaccine Success Stories Past & Present:

diphtheria

Before the introduction of a vaccine in the 1930s diphtheria was a common illness which was fatal in about 30% of cases [15]. The bacteria that causes diphtheria is easily transmissible between people and while some people can be asymptomatic it still remains infectious for up to four weeks [20]. Now, even with modern treatment methods and antibiotics, still 1 in 10 of unvaccinated adults and children who become sick with diphtheria will die [14]. However, the EPI has been so successful that in many Western countries like Australia most public health professionals have never seen a case of diphtheria [21]

pertussis

Also called whooping cough or the 100-day-cough, pertussis is transmitted from person to person by coughing, sneezing or being in close proximity of an infected person [34]. While the bacteria B. pertussis was isolated in 1906, it took until 1939 for an effective vaccine to become available, which along with other pertussis vaccine formulations is still in use today [13]. During 2019, approximately 125 WHO Member States achieved at least 90% coverage but rates are decreasing in wealthy countries [13]. Moreover, despite the success of the EPI, pertussis continues to be a leading cause of vaccine-preventable deaths. Although if caught early pertussis is treatable with antibiotics, like diphtheria, if untreated it kills 10% of children who become infected [13].

The high mortality rate in unvaccinated populations underscores why the WHO’s commitment to vaccine equity is so vitally important.

measles

Measles is one of the world’s most contagious diseases

- World Health Organization (WHO)

So contagious that, according to the ECDC (European Centre for Disease Prevention and Control), infectivity is close to 100% in unvaccinated and vulnerable populations [32]. Illustrative of how quickly an outbreak of measles can move through a population where immunisation rates have dropped below the level needed to provide ‘herd immunity‘ is the 2019 Pacific Measles Outbreak [45]. Unfortunately, even with all the technological advances in biomedicine, no measles specific treatments are available [33]. The virus can cause complications, especially for those with a weakened immune system, babies under one year, and pregnant women [16]. The infection can impair sight, and hearing, plus cause brain inflammation [4, 45]. The great news is the MMR vaccine, is not only 96% effective against measles, but it also protects against mumps and rubella too [36].

Infodemics are described as a tsunami of information during a health emergency or crisis [37]. This is particularly relevant during an outbreak of a disease like measles. Mis-, dis-, and mal-information (MDM-information) has been circulating since fraudulent research was published on the MMR vaccine at the turn of the century [35]. As the anti-vax movement has grown so to has the information generated by public health agencies promoting the safety of the MMR vaccine [35, 37]. This tidal wave of information, the so called ‘infodemic’, contains both good information and bad. This is where health literacy comes in, so people are empowered to be able to recognise what is trustworthy information and what is MDM- information.

To find out more about Infodemics read the article our Team collaborated on: Management of infodemics in outbreaks or health crises.

human papilloma virus (HPV)

Most HPV infections resolve spontaneously and are asymptomatic but recurrent and persistent infections can develop into cancer [5]. HPV is most associated with cervical cancer, but it can cause other types of cancers:

A vaccine against cancer-causing types of HPV exists, and being vaccinated significantly reduces the risk of these types of cancer developing for all genders [38]. Nearly two decades since the first HPV vaccine, there are now six prophylactic vaccines licenced [8]. Those vaccines have been incorporated into the national immunisation programmes for girls in 125 countries, with 47 of those countries offering it to all children [9]. Studies have already shown how effective the HPV vaccine is [6]. The most recent data from Scotland shows that in the 12 years since the HPV vaccine programme was implemented there have been zero cases of cervical cancer reported in women who were vaccinated when they were girls [18].

Edited and Produced by: Celine Tabche

In this video Dr Samiya, one of our Fellows, talks about her research on HPV Prevention in GCC Countries

Dr Samiya Al Khaldi, a family physician from Oman, is conducting her research on HPV prevention programmes in Gulf Cooperation Council (GCC) countries. Our fellowship programmes are tailored to suit each Fellows special areas of interest. This means Dr Samiya has been able to pursue research into promoting and implementing vaccination campaigns in national school programmes. Fully supported by our Team in achieving her goal of publishing scientific evidence to support the implementation of HPV vaccines in her community.

bacterial meningitis

Meningitis is an infection of the meninges, which are the membranes covering the brain [39]. Because many different pathogens, including bacteria, viruses, or fungi, can cause meningitis there is no universal vaccine [40]. However, progress has been made and there is an effective vaccine against some types of bacterial meningitis [40]. Welcome news as, of all the different pathogens that cause meningitis, the one that causes the highest global burden of disease (GBD) is bacterial meningitis [41].

In 2021, the WHO set out to achieve a vision for a meningitis free world by 2030 [42, 43].

In the road map “Towards a world free of meningitis” the WHO lists 3 goals:

elimination of bacterial meningitis epidemics
reduction of cases of vaccine-preventable bacterial meningitis by 50% and deaths by 70%
reduction of disability and improvement of quality of life after meningitis due to any cause

Our Team at the Imperial WHOCC have been collaborating with our colleagues in Iraq on research into the GBD of meningitis. Since 2018 there has been a significant shift in Iraq, with viral surpassing bacterial meningitis. We put this down to the impact of implemented vaccination strategies. The article Determining the Bacterial and Viral Meningitis Trend in Iraq from 2007 till 2023 Using Joinpoint Regression was recently published in Heliyon an all-science, open-access journal.

Raise Awareness:

Today people are starting to realise that unless everyone is safe from disease, nobody is truly immune. That is why WIW2024 aims to highlight individual actions, in parallel with the collective effort required of communities, to encourage families to vaccinate and protect themselves and their children. Raising awareness of vaccination safety and effectiveness is a key priority to increase childhood immunisation uptake. Let’s make this possible by taking steps to: