This piece was written by one of our contributors; Ireland-based doctor – Ciara Kelly.
As we continue to live through the global COVID-19 pandemic, one of the biggest and most frequently asked questions for healthcare professionals, scientists and governments alike has been – ‘When will we have a vaccine to protect us?’ And understandably so. 2020 has, to date, been a year marked by the ever-present threat of a new infectious disease, against which the vast majority of us do not have immunity. That’s an uncomfortable reality, as has been the uncertainty about when we might have a safe and effective vaccine available to protect us.
Around the world, we have all been closely watching the race to the development of vaccine against Sars-CoV-2 (the virus that causes COVID-19), and there are many different candidate vaccines out there. Last week saw, finally, a very good news story on this front – the exciting announcement by the UK government that they, on advice from the Medicines and Healthcare Products Regulatory Authority (MHRA), have approved the Pfizer/BioNTech coronavirus vaccine for use (1).
With work on-going on this new vaccination programme and plans for phased vaccination of the population over the coming weeks and months (2), it’s more important than ever to talk about vaccination and vaccine hesitancy, and to focus on facts over fiction.
Let’s go back to basics first.
What is a vaccine?
Vaccination can be defined as – ‘A product that stimulates a person’s immune system to produce immunity to a specific disease, protecting the person from that disease (3) .’ Immunity against a particular disease is achieved via the development of antibodies against it. There are two types of immunity to understand – active and passive.
Active immunity develops when exposure to a disease organism causes our immune system to produce antibodies against it – this exposure could be via administration of a vaccine, or through infection we acquire naturally.
Passive immunity, on the other hand, is what results from giving a person pre-formed antibodies (as opposed to the immune system producing them) – for example, antibodies passed from mother to infant prior to birth.
Now, there are many different vaccines out there which you’ll likely have heard of – such as the MMR (measles-mumps-rubella) vaccine, the seasonal influenza vaccine, the HPV (Human Papillomavirus) vaccine, and many others – plus, of course, the one the world is waiting for, the vaccines in development against Sars-CoV-2.
It is hard to underestimate the degree to which vaccination has transformed our health for the better – it is easily one of the most significant and impactful public health interventions out there, one of the greatest achievements of modern medicine to date. There are vaccines available to protect us against a wide range of infectious diseases, and the speed with which efforts have progressed this year to produce a vaccine against Sars-CoV-2 is testament to the pace of science and technology in our modern world.
Vaccines and Public Health
As a public health doctor with a significant social media following, I talk a lot about the importance of vaccination, and I follow many fellow medics and other healthcare professionals who do the same. Yet, despite this, there remains an almost never-ending stream of myths and misinformation online regarding vaccination, which remains a significant challenge, thanks in no small part to social media. The global demand and race for a vaccine for the Sars-CoV-2 virus is, in contrast, a welcome change from the virtual battle between vaccination science and anti-vaccination sentiment.
Vaccination is a public health intervention that brings benefits to both the individual, and the population they are a part of. For example, as I am a healthcare worker, it is recommended (in Ireland and the UK) that I get the influenza vaccine every flu season. Doing so means I have received the best available protection from ‘the flu’ for that season. But the benefits don’t stop there. Through receiving the flu vaccine, and developing immunity against this illness, my contacts, such as my family, friends and colleagues at work, are conferred a degree of indirect protection too, because if I am protected, I can’t spread it to them, interrupting the potential for chains of viral transmission.
At the population level, the major benefit from vaccination is the concept of herd immunity, which refers to the protection from a disease afforded to the population as a whole, as once a sufficient amount of the population are vaccinated against it. To give a real-world example, 95% vaccination coverage for measles is the herd immunity threshold target set by the World Health Organisation. If countries achieve this level of vaccine coverage, the incidence (number of new cases) of measles will decline because a sufficient proportion of the population will be immune to it. England sadly lost it’s ‘measles elimination’ status in 2019, due to the large increase in confirmed measles cases year on year since achieving elimination status in 2017. Sub-optimal uptake of the MMR vaccine (which requires two doses as part of the UK childhood immunisation schedule) is thought to have contributed to this (4).
There is a spectrum of beliefs regarding vaccination – from vaccine acceptance (persons who are pro-vaccination, with high levels of trust in their healthcare providers, who typically are fully vaccinated), to vaccine rejection (persons who are anti-vaccination, with low levels of trust in their healthcare providers).
It is the group in between acceptance and rejection, the ‘vaccine hesitant’, that are of particular interest to us public health. Ultimately, we want to bring people to the acceptance end of the vaccine belief spectrum, to enable us to protect as much of the population as possible. In 2012, the WHO Strategic Advisory Group of Experts (SAGE) on Immunisation established a working group on vaccine hesitancy (5), and defined it as follows:
‘Vaccine hesitancy refers to delay in acceptance or refusal of vaccines despite availability of vaccine services.’
Vaccine hesitancy was identified as one of the top ten threats to global health in 2019 by the WHO (6). It is a complex issue, and importantly, a context specific one. Vaccine hesitancy itself is also a continuum – persons who are hesitant about vaccines are not all the same. To help us understand vaccine hesitancy, the SAGE described the 3 Cs model;
- Confidence (5)
Let’s look at each in more detail.
Vaccines have been dubbed ‘victims of their own success’ (7). Diseases that vaccines protect us against have largely become rare, resulting in reduced fear, knowledge and recognition of them. This influences our perception of risk and therefore our likelihood to take up vaccines against them if offered. Individuals instead may weigh up the risk of vaccine side effects against the risk of such diseases which are no longer common – the short and long-term effects of which they may never have seen or experienced for themselves. We are seeing this changing perception of risk in the context of the Sars-CoV-2/COVID-19 pandemic as well, reflected in the variation of compliance with public health restrictions and guidelines across the population in Ireland and the UK.
We all love when things are made easier for us, and when it comes to vaccination, this is where convenience comes into play. There are a number of factors that influence vaccine convenience, such as the physical availability, affordability, accessibility, and context of delivery of the vaccine. In addition, factors such as language barriers and health literacy are relevant here too. For example, each year there is a flu vaccine clinic or service set up in hospitals to make it easy for staff to get vaccinated. By removing modifiable barriers and making vaccines more conveniently accessible to people we can improve the chances of vaccine uptake.
The SAGE defined confidence in the 3 Cs model as ‘trust in 1) the effectiveness and safety of vaccines; 2) the system that delivers them, including the reliability and competence of the health services and health professionals and 3) the motivations of the policy-makers who decide on the needed vaccines (5).’ That’s pretty self-explanatory and makes a lot of sense. Having confidence in the healthcare interventions we receive is so important, from the level of the intervention itself to the person(s) delivering the intervention to the people who have decided it is needed. We know healthcare providers are the most trusted source of advice and influence regarding their patient’s vaccination decisions (6). If you trust your doctor and value their opinion, there is a greater chance that you will be able to collaboratively come to decisions about treatments and preventative interventions such as vaccination. And collaboratively decision-making in medicine is a crucial part of the patient-centred care we strive to deliver.
This is a lot of information to take in. So let’s reflect for a minute. Vaccine hesitancy is a major threat to global public health. The purpose of this article is to help us understand why vaccine hesitancy is a public health concern, and what the factors that affect it are – remember, complacency, convenience, confidence.
If you’re a healthcare professional reading this, take some time to think about how those factors might come into play in your own interactions with your patients. How can you, and we, reduce complacency, improve convenience, and increase confidence, among our patients and the general public? This is a big question, one which is the subject of ongoing research (hopefully I’ll write a follow up article on that sometime!), but it’s worth reflecting on in your own practice. Addressing vaccine hesitancy (and the myth and misinformation that can drive it) requires a collaborative effort across many different healthcare disciplines – and central to doing so is effective, respectful, and compassionate communication, with each other, our patients, and the general public. Remember, it is the health of current and future generations and their communities that we are all working to protect (8).
And if you are a member of the general population, without a background in science or healthcare, I hope this article has been informative and helpful for you. Please, please speak to your family doctor if you have questions or concerns about vaccination, for yourself or others in your care – they’ll be more than happy to help and advise you. Remember to stick to credible, trust-worthy sources of health information online. The NHS also has an excellent web page dedicated to vaccination-related frequently asked questions, which you can find here (9).
(1) Department of Health and Social Care. UK authorises Pfizer/BioNTech COVID-19 vaccine. 2020. Available at: https://www.gov.uk/government/news/uk-authorises-pfizer-biontech-covid-19-vaccine
(2) Department of Health and Social Care. Independent report: Priority groups for coronavirus (COVID-19) vaccination – advice from the JCVI, 2 December 2020. 2020. Available at: https://www.gov.uk/government/publications/priority-groups-for-coronavirus-covid-19-vaccination-advice-from-the-jcvi-2-december-2020/priority-groups-for-coronavirus-covid-19-vaccination-advice-from-the-jcvi-2-december-2020
(3) Centres for Disease Control and Prevention. CDC Healthy Schools: Vaccine Basics. 2019. Available at: https://www.cdc.gov/healthyschools/bam/diseases/vaccine-basics.html
(4) Public Health England. Public health matters: Measles in England. 2019. Available at: https://publichealthmatters.blog.gov.uk/2019/08/19/measles-in-england/
(5) World Health Organisation. Report of the SAGE Working Group on Vaccine Hesitancy. 2014. Available at: https://www.who.int/immunization/sage/meetings/2014/october/1_Report_WORKING_GROUP_vaccine_hesitancy_final.pdf
(6) World Health Organsation. Top ten threats to global health in 2019. 2019. Available at: https://www.who.int/news-room/spotlight/ten-threats-to-global-health-in-2019
(7) Orenstein, WA and Ahmed R. Simply put: Vaccines save lives. 2017. Proc Natl Acad Sci USA. 114(16): 4031-4033. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5402432/pdf/pnas.201704507.pdf
(8) The Lancet Child and Adolescent Health. Vaccine hesitancy: a generation at risk. 2019. 3(5): 281. Available at: https://www.thelancet.com/action/showPdf?pii=S2352-4642%2819%2930092-6
(9) National Health Service. Vaccinations. 2020. Available at: https://www.nhs.uk/conditions/vaccinations/