Health experts remind medical frontliners to follow guidelines on COVID-19 vaccine booster shot

Pfizer's COVID-19 vaccine

Health experts said that individuals who are eligible to get a COVID-19 vaccine booster shot should follow the guidelines set by the Department of Health (DOH).

Members of the DOH’s Technical Advisory Group said that fully vaccinated medical frontliners should only receive one booster shot.

"Overdose here would be defined as more than what we recommend...From a safety principle standpoint, you really want to give the lowest possible dose that you know is going to be effective, otherwise, you will increase the risk of reactions," said TAG Member Dr. Edsel Salvana during a town hall event on Wednesday, Nov. 17.

"We have to stick to these current doses...We don't know what will happen to these people (if they take additional shots than what was recommended), and that is why we always say, please follow whatever is being advised by the experts," he added.

Is it safe to take the booster shot before the recommended six-month timeline? DOH TAG member Dr. Anna Ong-Lim said they are not recommending it.

"Ang basis kasi ng booster is really naka-based siya doon sa (The booster dose is based on) antibody responses. There is such a thing as optimizing these responses. From what we know right now, the data supports boosting on the sixth month onwards," said Ong-Lim.

"The state of knowledge that we have for these vaccines is so recent. Let's try to stay within the guidelines para hindi tayo masyado magkaroon ng unforeseen consequences. Bottomline, it is better to wait until your sixth month before reporting for your boosters," she added.

The experts were also asked how long the protection of the booster shots will last. Salvana said it remains uncertain.

“The answer to that is no one knows because this is gonna be a prospective thing that we have to see. And also, we are actually not even sure just how well these boosters are going to work. That is why we need to emphasize that this data is nowhere near as good as (compared to) the data that we have in the primary series of vaccines,” said Salvana.

“Kaya lang nilalabas ito, kasi there is some data that is showing that there may be waning of clinical protection, particularly against mild disease after six months. But the protection against severe disease remains,” he added.

To note, the Philippines has started administering booster shots for healthcare workers on Wednesday.

A fully vaccinated health worker can get a booster shot at least six months after he or she received the primary series----and three months if he or she got the Janssen vaccine as the primary vaccination.

Based on DOH Memorandum 2021-0484, medical frontliners have the option to receive a "homologous" or "heterologous" booster dose.

The DOH defined homologous dose as the administration of a COVID-19 vaccine from the same brand that was used to complete the primary vaccine series. The heterologous dose uses a vaccine from a different brand.

As a heterologous booster dose, the DOH said:

  • Individuals given Sinovac: may be given AstraZeneca, Pfizer, or Moderna.
  • Individuals given AstraZeneca: may be given Pfizer or Moderna.
  • Individuals given Gamaleya’s Sputnik V: may be given AstraZeneca, Pfizer, or Moderna.
  • Individuals given Janssen: may be given AstraZeneca, Pfizer, or Moderna.
  • Individuals given Pfizer: may be given AstraZeneca or Moderna.
  • Individuals given Moderna: may be given AstraZeneca or Pfizer.

The DOH also noted that the following volumes shall be administered:

  • Pfizer-BioNTech COVID-19 vaccine: 0.3 ml/dose
  • Moderna COVID-19 vaccine: 0.25 ml/dose (half of the regular dose)
  • Sinovac COVID-19 vaccine: 0.5 ml/dose
  • AstraZeneca COVID-19 vaccine: 0.5 ml/dose