January 31, 2021 — Preliminary epidemiologic indicators cited by Dr. Marissa Alejandria, president of the Philippine Society of Microbiology and Infectious Diseases, suggest that the SARS-CoV-2 variant B.1.1.7 detected by the Philippine Genome Center from a returning Filipino from the United Arab Emirates is associated with increased transmissibility. Currently, there is no evidence indicating that this variant has any impact on disease severity or vaccine efficacy. 

Dr. Alejandria who is also the Director of the UP Manila National Institutes of Health’s Institute of Clinical Epidemiology, presented this update during the 36th Stop COVID Deaths: Clinical Management Updates Webinar held on January 15, 2020. The topic was “Are You Afraid of the COVID-19 Mutations and Variants? A Public Health Perspective.”

The infectious disease specialist cited a January 13, 2020 PGC press release confirming the presence in the country of the variant following strengthened biosurveillance and border control efforts that led to the contacting of the person’s co-flight passengers. 

“The SARS-CoV-2 is an RNA virus and mutations arise naturally as the virus replicates. Many thousand mutations have arisen and the vast majority have no effect on the virus but are useful as a barcode to monitor outbreaks. The more viruses circulate, the more they may change and the changes can occasionally result in a variant that is better adapted to its environment,” Dr. Alejandria explained.

Using the definitions of Lauring AS and Hodcroft EB in JAMA 2021, she desribed a variant as a strain that has a demonstrably different phenotype (i.e difference in antigenicity, transmissibility, or virulence) and mutations as actual changes or errors in the sequences as the cell copies the genome. 

Silent mutations don’t change the resulting protein while non-silent mutations do change a protein sequence. Proteins are long chains of amino acids folded into different shapes. Each amino acid is encoded by three genetic letters but in many cases, mutations in the third letter of a trio will still encode the same amino acid. 

Dr. Alejandria identified the following as potential consequences of emerging variants: ability to spread more quickly in people, ability to cause either milder or more severe disease in people, ability to evade detection by specific diagnostic tests, decreased susceptibility to therapeutic agents such as monoclonal antibodies, and ability to evade natural or vaccine-induced immunity.

She noted that most commercial PCR tests have multiple targets to detect the virus such that even if a mutation impacts one of the targets, the other PCR targets will still work. She affirmed that both vaccination and natural infection produce a polyclonal response that targets several parts of the spike protein. The virus would likely need to accumulate multiple mutations in the spike protein to evade immunity induced by vaccines or natural infection. 

She assured vaccine effectiveness even for the new variant, pointing out that the new variant has mutations to the spike protein that the three leading vaccines are targeting. However, vaccines produce antibodies against many regions in the spike protein so that it is unlikely that a single change would make the vaccines less effective.

But she acknowledged that over time, as more mutations occur, the vaccine may need to be altered, as what happens to the seasonal flu which mutates every year so the vaccine is adjusted accordingly. The SARS- CoV-2 virus does not mutate as quickly as the flu virus and the vaccines that have so far proved effective in trials are types that can easily be tweaked. 

Both Dr. Alejandria and the succeeding speaker Dr. Evalyn Roxas, associate professor at the UP College of Public Health and president of the Philippine Hospital Infection Control Society, tackled the public health aspect and professed that since the modes of transmission are the same which are respiratory droplets and aerosols, the precautionary measures are the same. But discipline is needed for a stronger and more sustained compliance with protocols such as environmental and hand hygiene; wearing of mask, faceshield, and other PPEs; physical distancing; avoiding crowded or closed spaces; and avoiding prolonged closed contact interactions. 

The webinar’s reactors were Dr. Juan Javier Garchitorena, Unit Head of the Provincial COVID-19 Facility and a Doctor to the Barrios frontliner of the Dinagat Islands and Maria Fatima Lorenzo, President of the Philippine Alliance of Patient Organizations. CPH Dean Dr. Vicente Belizario, Jr. and UP Manila Chancellor Carmencita Padilla gave the opening and closing remarks, respectively.

Cynthia M. Villamor

Published in UP Manila Healthscape Special COVID-19 Issue No. 22