As booster shots for fully vaccinated healthcare workers begin rolling out on Nov. 17, the Department of Health (DOH) stressed that receiving boosters is voluntary since there is lacking data about how well boosters will work.
This leaves a number of questions in the public's minds: Should you get a different vaccine brand for your booster? Are booster shots safe? And when should you get it?
Homologous vs heterologous
Currently, the DOH offers healthcare workers the choice between getting the same vaccine brand as their primary series (homologous) or getting a different brand (heterologous), based on the brand mixing approved by the government.
But as DOH Technical Advisory Group's Dr. Edsel Salvana noted in a Facebook post, "There is data that mixing (heterologous vaccination) is more likely to cause reactions."
"However, hindi naman ito severe," he said in a DOH forum on Nov. 17. "It is a question of harm vs. benefit. We know that yung benefit right now, we're still looking at the data—a lot of this are unpublished, not peer-reviewed."
"We're not actually sure how well these boosters will work. Kaya lang nilalabas 'to kasi may waning of immunity from clinical disease," Salvana added.
Booster shots are given to those whose immunity is going down after they completed their primary vaccine series.
Healthcare experts, including DOH Undersecretary Rosette Vergeire, recommended going with homologous vaccinations as they have more consistent studies with regards to safety.
"For those with a history of adverse reactions to vaccines, it may be best to receive a homologous series due to its more consistent safety profile," she said.
Infectious disease expert Dr. Anna Ong-Lim added that they don't know what kind of protection mixing vaccine brands will offer.
"We don't know the added protection ng heterologous vaccines. The data is pointing that it might work for a special population. There is no guarantee that it will work for all."
She also discussed some considerations for those who are thinking of getting boosters. "Consider your risk and health status. The data is still evolving."
When should you get a booster shot?
The DOH announced that one booster shot will be given to frontliners at least six months after they received Sinovac, AstraZeneca, Pfizer, Moderna, and SputnikV, and three months after if they got the single-shot Janssen.
Ong-Lim said that "there is still room to wait" for boosters, especially if you don't work in a COVID ward.
She emphasized that people shouldn't be in a rush to get a booster dose. "Hindi naman ma-di-discontinue ang booster program. It will continue for A2 and A3 (senior citizens and persons with comorbidities)."
"If hindi ka A1, I would not [recommend going] for it yet," Salvana said.
The Center for Disease Control and Prevention put out a list of individuals recommended to get a booster dose, including those who are 65 years old and above, those who work or live in high-risk settings, and those with underlying medical conditions.
The priority of the DOH is still to get people vaccinated with their primary COVID-19 vaccine.