The World Health Organization (WHO) defines “herd immunity” as the indirect protection from an infectious disease like COVID-19 that happens when a population is immune either through vaccination or immunity developed through previous infection. The WHO underscored that achieving herd immunity through mass vaccinations is the only acceptable way to go.
The WHO has not prescribed a specific figure that will signify that herd immunity has been achieved, because “it (herd immunity threshold) will likely vary according to the community, the vaccine, the populations prioritized for vaccination, and other factors.”
Nevertheless, national media outlets has followed the lead of Health Secretary Francisco Duque, Jr. in putting at 70% of the current Philippine population. The 2020 national census revealed that there are now 109 million Filipinos, and 70% of that is 76 million.
According to number crunchers on social media like Edson Guido of ABS-CBN News and the people behind Herd Immunity PH, the Philippines can achieve herd immunity by March 2022 based on the ramped-up vaccination effort across the country. However, to borrow a term from economics, it must be understood that their estimate is based on a concept from economics called “ceteris paribus” – or “all things held constant.”
For example, because of the rampage of the much more contagious delta variant of COVID-19 around the world, the United States-based Becker Hospital Review has estimated that the herd immunity threshold is now at 80%. If that’s the case, the Philippine government will now have to target 88 million Filipinos for vaccinations.
Given these two circumstances, it means that the current estimated date as to when the Philippines can achieve herd immunity might be too optimistic. Nevertheless, the government can still take two critical course of actions: