So, what is this thing called the Covid Booster Shot?
The fact is that immunity against SARS-CoV-2 or the virus that causes Coronavirus disease (Covid)starts to wane 6 months after the last dose of the primary dose series of the Covid vaccine.
The primary dose series means the original 2 doses given to make a person fully vaccinated against Covid. In the case of Johnson & Johnson, the primary dose series would mean the first and one dose given which is already complete even if it is only one dose.
People who received their 2nd dose in the primary dose series 6 months or more ago, are already eligible for the booster shot.
There are 2 strategies for the booster shots roll out: the homologous and heterologous booster shots.
Homologous booster shot – this means that the brand of the booster vaccine is the same as the brand of the vaccine which the person got in the primary dose series. For example, if a person was inoculated with Sinovac during the primary dose series, then he/she can also get vaccinated for the booster shot using the Sinovac brand.
Heterologous booster shot – this means that the brand of the booster vaccine is not the same as the brand of the vaccine given for the primary dose series. For example, a person who got the Sinovac brand for his primary dose series is eligible to get a Pfizer-made booster shot.
Heterologous booster is associated with better immune response but known to present more side effects such as headache, fever, injection site pain, myalgia, body malaise etc. compared to homologous booster.
All side effects, however, are self-limited and usually last for 1-2 days.
The priority groups for Covid booster shot include the following:
- the health care workers
- senior citizens
- and people with comorbidities.
Getting a booster shot is voluntary but I highly recommend to everyone to get the booster shot since Delta variant is just around the corner ready to strike when his/her immune system is down.
Regardless of which primary dose series you got, you can choose one of these Covid vaccines as a booster shot:
- Pfizer
- Moderna
- and AstraZenica.
As of this writing, Sinovac can be used as booster for people previously vaccinated with Sinovac. No data is available, yet, whether or not, Sinovac can be used as booster for people who were given Pfizer, Astra, Sputnik, Moderna etc. as their primary dose. I repeat, as of this writing, Sinovac can be used as booster shot for people whose primary dose series was Sinovac.
Here are important things to remember:
- If you were inoculated using the AstraZenica vaccine as your primary dose, I suggest you choose Pfizer or Moderna as your booster shot and NOT AstraZenica. Why? It is because AstraZeneca uses VIRAL VECTOR technology. This VIRAL VECTOR will be destroyed by our preformed antibodies from previous AstraZenica vaccination, making VIRAL VECTOR of the AstraZenica vaccine less effective in eliciting an immune response.
- However, AstraZenica is slightly superior to Sinovac or Pfizer when it is used as booster dose for Sinovac vaccinated individuals.
- For people who have many allergies and anxious about vaccine related side effects, I suggest you get Sinovac as booster, which is applicable only if you used Sinovac in your primary dose series.
My other recommendations are:
- Those who originally got Sinovac for their primary dose series, can get as a booster the following: Sinovac, Pfizer, Moderna, and AstraZenica. Sinovac is preferred if a patient has many allergies or prefers less side effects.
- To those who were inoculated with Johnson & Johnson/Janssen (J&J) as their primary dose, they can get the same brand (Johnson & Johnson – J&J) if the primary dose was given 3 months ago. For those who got J&J about 6 months ago, it is best to use Moderna, Pfizer or AstraZenica as the brand for the booster shot.
Theoretically AstraZenica is less preferred since both J&J and AstraZenica use VIRAL VECTOR technology. This recommendation is not a safety issue but rather has something to do with efficacy.
- If a patient received Moderna in the primary dose series, the brand of the booster shot can be any of these: Moderna, Pfizer or AstraZenica.
- For those who got Pfizer in the primary dose series, the booster shot could be either Pfizer or Moderna.
- Moreover, those people who got AstraZenica in the primary dose series, should be getting either Pfizer or Moderna as a booster shot.
Again, VACCINATION remains the best weapon against the possible complications arising from Covid infection.