We have all heard and used the terms vaccination and immunisation many times, particularly over the past two years.
However, now that our discussions are as common at BBQ’s as with our healthcare professionals, it’s likely we have heard
or used the terms interchangeably… but that’s not quite right.
What’s the difference?
Vaccination is the act of introducing a vaccine into the body to gain protection from a specific disease.
It includes both receiving an injection, like the COVID-19 vaccine, and taking an oral vaccine dose, such as Rotarix® -
the oral vaccine given in Aotearoa New Zealand when babies are 6 weeks and 3 months as part of their Childhood
Immunisation to preventrotavirus infection.
Alternatively, immunisation refers to the process of becoming immune to a disease following vaccination so it's the
result of successful vaccination.
Importantly, this means that developing immunity, or protection to a disease comes from having the right vaccination.
The COVID-19 vaccination will protect you from the known variants of the virus in the COVID-19 pandemic, but it will do
nothing to protect you from different viruses such as influenza (flu), which requires a different flu vaccination.
How do vaccines work?
Regardless of the method or type of vaccine used, immunisation occurs in much the same way. When a vaccine is
administered, most (but not all) people will produce a natural immune response just as they would following an exposure
to the disease, but without getting the disease itself. If successful, this experience of the disease is ‘remembered’ by the body’s natural defence mechanisms, allowing future infections to be responded to much more strongly than it could
without the vaccination.
However, protection from the disease doesn’t simply happen as soon as you are vaccinated. Usually, an immune response
will take about 2 weeks as the body learns to respond to the foreign substance it was introduced to. A common
side-effect is to experience mild symptoms like an ache in the arm that received the injection as this occurs.
Some vaccinations need to be given multiple times to build long-lasting protection, such as the two doses of MMR needed
to build protection from measles, mumps and rubella, the multiple COVID-19 vaccinations and booster doses and why there
is a detailed schedule of Childhood Immunisations - 13 vaccinations in all between 6 weeks and 4 years of age.
Another critical aspect to understanding the way that vaccines work is to look, not just as the individual becoming
immunised, but at the role this plays within whānau and society at large. Some people can’t be vaccinated against some
diseases, and some people are particularly prone to adverse outcomes from disease (more on this later). If everyone that
can be, gets vaccinated (even those who feel the risk to them personally is low), as a whānau, community and country we
will all be better off as the virus that spreads the disease is prevented from moving between people and eventually dies
off stopping the outbreak.
How long does immunisation last?
Completing the full course of vaccinations is vitally important in building the advised level of immunity. A child who
has been given some of their schedule of vaccinations is only partially protected. This means a child that has missed
doses of the DTPa vaccine for example, remains at risk of diphtheria, tetanus and pertussis (whooping cough) and may
become sick if exposed to these diseases until they have had their full schedule of vaccinations.
Even having had the full course, the protective effect of immunisations is not always lifelong. Vaccines like tetanus
will generate effective protection for around 10 years, after which time a booster dose may be given. Immunisations such
as whooping cough vaccine give protection for only about 5 years after a full course, and the influenza vaccination or
Flu Jab is needed every year due to frequent changes to the type of flu virus in the community. In fact, flu jabs are
particularly important this year given the absence of influenza over recent years and the reduced immunity within the
public.
The potential rollout of an additional booster against COVID-19 for the most at risk groups is also based on the fact
that the immunity developed from vaccines diminishes over time. It is why even if you have developed immunity from
having a disease, that vaccination after infection is recommended to bolster immunity.
Can everyone be vaccinated?
Immunocompromised people, those with certain medical conditions that cause immunodeficiency, or those taking medications
that reduce their body’s immunity, such as cancer treatments, may be unable to have certain vaccines.
This may be because their immune system isn’t working as well as it should to protect them from infection—or that their
immune system can’t distinguish between normal and foreign cells and so isn’t able to create an immune response to the
vaccination.
It can’t be stated enough – vaccination benefits you and the people around you. It is important that those people that
can get vaccinated and become immunised, do so. If enough people in the population become immunised against a disease,
such as measles, then it becomes much harder for the virus to spread and potentially infect those most at risk of severe
illness.
Experts predict that measles is expected to be re-introduced to NZ at any time. Measles is one of the most infectious
diseases in humans and is now the third most common vaccine-preventable cause of death among children throughout the
world.
The more people who have protection through the MMR vaccine, the less cases we will have in the community, the less risk
there will be for babies not yet old enough to receive their MMR, the less pressure there will be on the health system
to manage an outbreak. Also, the less people that will have to isolate as contacts of cases, as unlike COVID-19, if you
have had both doses of the MMR vaccination, you do not need to isolate after being in contact and will be able to
continue to work, study, shop or socialise as normal.
How well are we doing?
Aotearoa’s COVID-19 vaccination rates for the original two doses are amongst the highest globally, and around 94% for
the Waikato. However, our other vaccination rates have decreased significantly. The uptake of important COVID-19 booster
vaccinations is far lower than desired, with the Waikato region still only at around 69%; and lower again for Māori at
52% and Pacific at 61%.
The number of people getting a flu vaccination began promisingly back in April, but rates have dropped week by week
since, a concern with flu now in the community and spreading. Plus, with COVID-19 also still in the community, experts
fear that the potential to develop co-infection, to have both at the same time, could make people particularly sick,
even if they are currently fit and healthy.
According to Waikato DHB Medical Officer of Health Richard Vipond, vaccination is without doubt the leading medical
intervention in recent history, saving millions of lives from potentially fatal diseases globally. Despite this, we
continue to see outbreaks of immunisation-preventable diseases such as measles and whooping cough (pertussis) here in
Aotearoa.
“We are failing to reach immunisation targets for one of our most vulnerable groups - our babies and tamariki, despite
multiple attempts over the years. The COVID-19 pandemic has worsened the situation, but rates have been declining since
2017,” says Dr Vipond.
As of 31 December 2021, national childhood immunisation rates have dropped to 85.2% for 2-year-olds over the 12-month
reporting period, well away from our goal of 95%.
We are also seeing worsening ethnic disparities, with Māori most significantly affected. While national fully-immunised
childhood rates were at 85.2% in 2021, Māori had a rate of just 72.9%. This gap has increased since the peak in 2017, at
which time Māori immunisation rates were as high as 91.8% comparable to the national rate of 92.8%.
“We need to increase these rates and we need to do it quickly,” says Dr Vipond.
“Vaccination is an action, but immunisation is the outcome and it’s what we are trying to achieve. We need protection
for our tamariki, our kaumatua and kuia, and ourselves from diseases that are either entirely preventable, or that we
can and should significantly increase our protection from.”
“Every day people go unprotected is another day they, and both our young and old, are at risk of serious, but
preventable illnesses.”