High-efficacy vaccine vital in having ‘herd immunity’

Published November 25, 2020, 9:58 AM

by Noreen Jazul

Even with population immunity, health protocols must still be observed

An infectious disease expert said inoculating more than half of the population against COVID-19 is enough to create “herd immunity” but only if the vaccine administered has high efficacy. 


In an interview with DZMM, Dr. Rontgene Solante, infectious disease director of San Lazaro Hospital in Sta. Cruz, Manila, said vaccine efficacy is important in determining how many persons should be vaccinated to achieve “herd immunity.” 

“Importante na ang bakuna na ibibigay natin dito is mataas ang pursyento na mabisa siya. 

Dahil kung medyo mababa din, di mas marami tayong babakunahan di lang siguro 60 percent (It’s important that the vaccine has high efficacy because if not, we may need to inoculate more people, not just 60 percent of the population),” Solante told DZMM in an interview Wednesday. 

Health Secretary Francisco Duque III had earlier said the government’s goal is to achieve “herd immunity” by vaccinating 60 to 70 percent of the population. 

‘What is herd immunity?’ 

“Herd immunity” or “population immunity” is defined by the World Health Organization (WHO) as a “concept used for vaccination, in which a population can be protected from a certain virus if a threshold of vaccination is reached.” 

WHO said vaccinating the “vast majority” of a population, will lower the “overall amount of the virus’ ability to spread” in a population. 

“As a result, not every single person needs to be vaccinated to be protected, which helps ensure vulnerable groups who cannot get vaccinated are kept safe,” the WHO said. 

Solante, for his part, explained that “herd immunity” is vaccinating a certain percentage of the population to help stop the spread of a virus. 

The infectious disease doctor said vaccinating more than half of the population will in turn “create an immunity even to those who has not [been vaccinated] or di pa nakatanggap ng vaccine [yet to be vaccinated] dahil majority na ng population ang nagde-develeop ng antibody para di na mag-spread ang virus (because majority of the population are already developing antibody which will then prevent the spread of the virus).” 

‘Health protocols should remain’ 

Solante, however, said the public and the government should not be complacent even if the country achieves “herd immunity.” 

“Di naman lahat mababakunahan, [kaya dapat] paigtingin pa rin yung mga health protocols natin na ginagawa (Not all will be vaccinated, that’s why stringent health protocols should remain in place),” Solante said. 

When asked which population groups will likely be prioritized for vaccination, Solante identified four – the frontliners, persons with comorbidities, non-healthcare but essential workers, and the elderly. 

Solante said he expects a vaccine to be created by the second or third quarter of next year.