Lets start clearing the confusion around Covid – As we approach what many hope will be a transition from pandemic to endemic, Australians, as with the people of many other countries, are a mix of citizens with contrasting views and conflicting experiences of Covid-19.
While some continue to deny its existence, others have experienced mild sickness from Covid, thousands have come close to dying from it, and sadly, more than 4500 victims of the virus are no longer with us to share their stories.
So, how should community pharmacists and pharmacy assistants approach conversations on the topics of vaccination, immunity, boosters and what to expect now from Covid-19?
As one of the top three most trusted professions in Australia, community pharmacists and their staff are in an influential position when it comes to dispelling the myths and educating patients.
Vaccination
The Australian Academy of Science in partnership with the federal Department of Health has created an online information booklet, ‘The science of immunisation: questions and answers’.
The booklet explains immunisation in clear and easy-to-understand language, with the aim of supporting people to make good health decisions based on science.
Among the questions answered are:
- What is immunisation?
Vaccines work by stimulating the body’s defence mechanisms to provide protection against infection.
Vaccines can sometimes produce a stronger, longer-lasting protective response compared with immunity from a natural infection.
Vaccines create immunity without causing diseases that can lead to serious complications, which is why vaccination is a safer way to develop immunity.
- What is in a vaccine?
The main ingredient is antigens, which, when used in a vaccine, are designed to trigger a specific protective response by the immune system to a specific pathogen. Therefore, each vaccine contains a different set of antigens.
These could include killed whole pathogen, components of the pathogen and inactivated toxin produced by the pathogen.
- Who benefits from vaccines?
a) The individual benefits: An effective vaccine protects an individual against a specific infectious disease and its complications.
In the short-term, vaccine efficacy is measured by its ability to reduce new infections. The longer-term goal is to reduce serious complications and death.
b) The community at large benefits: Most vaccines not only benefit the individual who receives the vaccine, but also the entire population through a phenomenon known as herd immunity. Herd immunity occurs when a significant proportion of individuals within a population are protected against a disease through immunisation.
This situation offers indirect protection for people who are still susceptible to the disease, by making it less likely that they will come into contact with someone who is carrying the pathogen. Vaccination is the best way to create the right conditions for herd immunity to develop.
- Are vaccines safe?
People are more likely to experience a serious complication from Covid-19 infection than from any of the currently approved Covid-19 vaccinations.
Do I need the vaccine if I’ve already had Covid-19?
The Australian government recommends vaccination for people who have had Covid-19.
If they’ve had a laboratory-confirmed Covid-19 infection, they can delay Covid-19 vaccination by up to four months after recovering. This is because, after Covid-19 infection, the risk of reinfection is reduced for at least four months.
Testing using PCRs or RATs to detect current or previous infection with Covid-19 before vaccination is neither necessary nor recommended before vaccination.
There is no requirement to delay vaccination. However, patients may choose to be vaccinated within four months after recovery from Covid-19 if they:
- Are significantly immunocompromised and may be at greater risk of further Covid-19 infection.
- Have a job that requires them to be vaccinated.
- Have a job that puts them at greater risk of being exposed to Covid-19.
Patients should not be vaccinated until they’ve recovered from the acute illness. People with a past Covid-19 infection should receive two doses of the Covid-19 vaccine and subsequent boosters when they are due.
What is the difference between natural immunity and vaccination?
There’s little difference, other than in the sickness that occurs through Covid-19 infection, which carries a significantly higher risk of being serious than vaccination.
However, due to the nature of the Covid-19 virus, both natural immunity and vaccination immunity gradually decrease over time.
How long does immunity last?
Research published in October 2021 by the Yale School of Public Health and the University of North Carolina in the US has found high levels of protection following natural infection of Covid-19 to be short-lived.
The study is said to be the first to determine the likelihood of reinfection following natural infection and without vaccination.
The researchers conclude that, in endemic conditions, reinfection by the virus would be likely to occur between three months and five years after the subject’s peak antibody response, with a median of around 16 months.
However, the paper’s lead author, Professor Jeffrey Townsend, says that, in some cases, reinfection time could be even less.
“Reinfection can reasonably happen in three months or less,” he said. “This shows those who have been naturally infected should get vaccinated. Previous infection alone can offer very little long-term protection against subsequent infections.”
The research team analysed reinfection and immunological data from the closely associated viral relatives of SARS-CoV-2 that cause common colds, as well as data from SARS-CoV-1 (SARS) and the Middle East respiratory syndrome (MERS).
They combined genetic data from those viruses with the SARS-CoV-2 virus, creating a model to show how viral behaviours evolve over time and enabled the team to estimate the time frame for Covid-19 antibody levels to decline post-infection, alongside additional factors needed to understand reinfection risk.
This allowed the researchers to build a model predicting the likely reinfection risk after Covid-19 is endemic.
That model suggests the average reinfection risk increases over time, ranging from around five per cent four months after the first infection, to around 50 per cent after 17 months.
The study’s authors say this period of protection is less than half the duration known to exist for other endemic coronaviruses circulating among humans.
With this clearer picture regarding Covid-19 infection and the increased risk of reinfection over time, we can see that vaccination and boosters are important tools in managing individual health.
While a high proportion of the eligible population has been double vaccinated, it’s important to get the message out regarding the decreasing levels of protection, and the increased risk to those choosing not to receive booster shots.
This feature was originally published in the March issue of Retail Pharmacy Assistants e-magazine. To read the feature in full as it appears in the e-magazine, visit: rpassistants.com.au/retail-pharmacy-assistants-march-2022
