Things are seemingly, cautiously going back to pre-COVID normalcy, but according to certain studies, the immunity of COVID-19 vaccines is waning, and the booster dose was introduced and rolled out. In short, it’s an “add-on” vaccine after being fully vaccinated, though according to this article, 40% of booster dose recipients in Malaysia do not show up for their appointments. There’s a lot of debate surrounding the COVID-19 booster dose, so hopefully this can help clear things up for you, and help you make a decision in regards to the booster dose!
Note: This article was produced based on online research to the team’s best ability and vetted by medical personnel, but NOT intended as expert advice. Please consult your doctor or utilise these telemedicine apps if you have any concerns.
What’s a Booster Dose/Why is It Called a Booster Dose?
First things first, let’s get to know what’s a booster dose, or how it got its name. The booster dose, or booster shot, is basically an extra dose of a vaccine after an earlier (original or primary) dose has been administered. In other words, it “boosts” your immunity, and therefore earned its name as a booster dose. Despite having a different name, the COVID-19 booster dose formulation is the same as the “original” vaccines, with the exception of Moderna booster doses. For Moderna, the booster dose is half the amount of the initial vaccine.
What Does a Booster Dose Do?
Booster doses re-expose one to the immunising antigen, intended to increase immunity against that antigen back to protective levels, as immunity may wane after a certain period of time. Booster doses can be administered weeks, months, or years later. As a side note, not all vaccines require a booster dose, and it’s unclear why certain vaccines require boosters, while others do not. A hypothesis is that if the immune system responds to a primary vaccine rapidly, the body does not have time to sufficiently develop immunological memory against the disease, and memory cells will not persist in high numbers for the lifetime of the human.
*ANTIGEN: Any substance capable of stimulating an immune response/generating antibodies.
Why Get a Booster Dose?
Immunological studies have shown that antibody levels among vaccinated individuals (for COVID-19) experience a steady decline over time, and a long-term follow up of vaccine trial participants also go through a growing risk of breakthrough infection. Furthermore, there are records from countries including Israel and the UK among other countries that show that the COVID-19 vaccines are losing their strength, though they are still holding up well in preventing death, hospitalisation, and severity of the disease, as is the primary intent of the vaccines. Certain people may also be more at risk despite having been fully vaccinated, and we explore who should get a booster dose below. The performance of the vaccines may also be not so effective in preventing against current strains.
Who Should Get a Booster Dose?
Recommendations by the World Health Organisation (WHO) Strategic Advisory Group of Experts on Immunisation (SAGE):
- People who did not respond adequately to the initial doses (immunocompromised)
- Senior citizens above the age of 60
- Frontliners (Healthcare workers)
Our Ministry of Health is also developing a strategy to roll out the booster dose to the categories below, according to this article:
- Those above 18 with comorbidities
- Individuals above 40
- Pregnant women
- Frontliners apart from healthcare workers
*IMMUNOCOMPROMISED: Your immune system’s defences are low. This can be a temporary or permanent condition, depending on how the immune system is compromised.
*COMORBIDITIES: The simultaneous presence of two or more diseases or medical conditions in a patient.
Can I Mix and Match the Booster Dose and Initial Vaccine Brands?
The short answer is yes, and we’re currently doing it as well. Pfizer was the first to develop booster doses, which made it the only option for some time. Research about mixing and matching vaccine brands or receiving a booster dose of the same brand yields various results, but the general consensus is that it’s safe to receive the Pfizer booster dose even if your initial vaccine is of a different brand. For Sinovac vaccine recipients, the Pfizer booster dose is recommended by default as studies based in Thailand show that this combination is 90% effective. You can also read more about clinical trials on mixing vaccine brands here and here.
Can I Take a Sinovac or AstraZeneca Booster Dose?
The short answer, again, is yes. In fact, the Sinovac booster shot has been approved and is being used in China, Turkey, Chile, Indonesia, and Cambodia, while six other countries are waiting for approval from their respective regulatory authorities. In Malaysia, as of 12 November, AstraZeneca and Sinovac have submitted their dossiers and the Ministry of Health is in the process of reviewing it. Once they are approved, whether or not Pfizer would still remain as the default booster shot is unclear. We will just have to sit tight and wait for more news!
We hope this has been a helpful read in regards to booster doses, so depending on personal conditions, you should be able to gain a better understanding and make a sound decision for yourself. As always, speak to a professional regarding any doubts you may have, and continue to practice good hand hygiene, and maintain social distancing! Stay safe!