New COVID Booster: Eligibility And Benefits Explained

Targeting the Spike Protein

This new booster, as well as other vaccines in the market, are based on mRNA technology. This technology works by instructing our cells to produce a protein found on the surface of the SARS-CoV-2 virus, specifically this protein is known as the spike protein. The spike protein is essential is vital for the virus to attract to enter human cells, and by the production of antibodies to this protein, the virus can be neutralized.

However, as the virus continues to mutate, the spike protein changes as well. This is due to what’s known as immune pressure: as our immune systems get better at recognizing the virus, the virus adapts by modifying its structure to evade recognition. Since the onset of the pandemic, Omicron sub-variants like JN.1 have emerged, making vaccines targeting older strains less effective. The JN.1 sub-variant, first detected in August 2023, has since spawned additional sub-variants, further complicating efforts to keep up with the virus’s evolution.

The spike protein consists of 1,273 amino acids, which can mutate over time, changing the structure of the protein. This allows the virus to escape some of the antibodies generated by previous infections or vaccinations. It makes it crucial for vaccine developers to constantly update their formulas in order to ensure the spike proteins in vaccines closely match those present in the virus circulating in the population. The better the match between the vaccine and the virus’s spike protein, the better the protection it offers.

Who Should Get Vaccinated, and When?

Updating vaccines for mutating viruses is not a new concept. For example, the flu vaccine has been updated every year since the 1950s to keep up with the influenza virus. However, unlike the flu, COVID-19 has not yet settled into a predictable annual cycle. COVID-19 continues to appear in waves, making it a constant challenge. Additionally, COVID-19 is much more contagious than the flu, with estimates showing that one person infected with the JN.1 sub-variant can spread it to five others, compared to just 1.3 for the flu. This makes COVID more difficult to contain.

Furthermore, immunity from COVID vaccinations (or previous infections) tends to wane over time, meaning boosters are needed to maintain high levels of protection. For certain vulnerable populations, this may require more frequent boosters than the annual doses recommended for the general population.

The TGA recommends that people aged 65 to 74 receive a COVID booster every 12 months, though they are eligible every six months. For those aged 75 and older, the recommendation is to get a booster every six months. Adults between the ages of 18 and 64 are eligible for a booster every 12 months unless they have a severe immune deficiency. Conditions such as autoimmune diseases, diabetes, lung disease, and certain cancer treatments are examples of conditions that could make someone eligible for more frequent boosters.

Making Sense of the Advice

It is expected that the Pfizer booster will be providing protection against the JN.1 sub-variant of Omnicorn, which has been predicted to dominate in the upcoming months. Although the TGA’s approval of the JN.1 booster is a step forward, the Australian Technical Advisory Group on Immunisation will need to provide further guidance before it becomes widely available. The rollout is expected to take place within the next month, potentially ahead of the holiday season for it is a time when many people gather with family and friends.

In the meantime, the XBB.1.5 vaccines remain available. While these vaccines were designed for an earlier Omicron sub-variant, they still offer some level of protection against the virus. It is expected that younger, healthier individuals may prefer to wait for the new JN.1-targeted booster, while vulnerable groups may benefit from getting vaccinated with whatever booster is currently available.

In vulnerable groups such as older adults and those with weakened immune systems, it is highly advised to get vaccinated regularly as these people are at a higher risk of severe illness, hospitalization, and death from COVID-19. For those with stronger immune systems and in healthy conditions, the vaccine can lower the risk of developing long COVID, a lingering condition that can affect multiple organ systems.

Do You Need a COVID Booster?

While the vaccines provide excellent protection against severe disease, it’s important to remember that they do not guarantee immunity from infection. COVID-19 vaccines are less effective at preventing mild illness or breakthrough infections, but they remain our best defense against severe disease and hospitalization. The evidence on whether vaccines reduce transmission of the virus is mixed, but there is consensus that vaccination reduces the overall burden of disease.

The rollout of the new Pfizer booster marks an important step in managing the ongoing COVID-19 threat. With the virus continuing to mutate and evolve, it is likely that future updates to the vaccine will be necessary to keep pace with new variants. However, it’s clear that vaccination remains a vital tool in reducing the impact of COVID-19 on both public health and individual lives.

As the holiday season and social gatherings approach, getting vaccinated can provide an extra layer of protection against the virus and help prevent community outbreaks. If you're due for a booster or have concerns about your vaccination, it's a good idea to talk to your healthcare provider to determine the best option based on your health and risk factors.

While it may take a considerable amount of time for COVID-19 to fade away, updated vaccines can help curb the severity of the illness, protect vulnerable groups, and assist in managing future waves of infection. Vaccinations stand as a vital tool in the ongoing fight against COVID-19 as we continue to live with the virus.