Omicron variant

COVID-19 Weekly Watch: Tracking Omicron’s dominance

Sofia Tomacruz
COVID-19 Weekly Watch: Tracking Omicron’s dominance

CHECK. Quezon City authorities check on vaccination cards of commuters on the first day of the DOTR's 'no vaxx, no ride' policy on January 17, 2022.

Angie de Silva/Rappler

This week of January 24, 2022, we're watching Omicron's track across the country and how sewage could aid health surveillance efforts

Coronavirus cases have started to decline in Metro Manila and some nearby provinces, while cases in the rest of Luzon were showing signs of plateauing, after weeks of tallying record infections. 

But it’s a different story for the Visayas and Mindanao, where cases have seen a sustained increase. On places to watch, the Department of Health says Western Visayas, Central Visayas, and Davao Region have the highest average of COVID-19 cases. 

Here’s what we’re watching this week of January 24, 2022: 

Overtaking Delta

After weeks of explosive growth in COVID-19 cases, genomic sequencing has shown Omicron is now the dominant variant in Metro Manila. It edged out Delta, which had been the predominant variant for the most of 2021.

  • Omicron ousted Delta in just about two month’s time. Health Undersecretary Maria Rosario Vergeire said on Wednesday, January 25, that from taking up 1.30% of samples in November, Omicron now accounted for 98.9% of samples by January.
  • It was the same case for other parts of the country, where trends and the characteristics of Omicron were seen in increasing cases. 
  • Both Omicron, known as BA.1, and a BA.2 subvariant dubbed as “stealth Omicron” have been detected in the county. The Omicron BA.2 subvariant turns out to be the predominant variant in most regions. Meanwhile, BA.1 was detected in only 8 regions, including Bicol region, where it was predominant. BA.1 was also the predominant variant among returning overseas Filipinos.
    • The Omicron subvariant was called “stealth Omicron” because it “has many mutations in common with standard Omicron, but it lacks a particular genetic change that allows lab-based PCR tests to be used as a rough and ready means of flagging up probable cases,” The Guardian reported.
    • When it comes to how one should treat it, local health officials said data so far showed there is “no significant difference” in how BA.1 or BA.1 present clinically. More data is also needed to understand this subvariant, but experts have repeatedly stressed that health measures continue to work against circulating variants. 
Must Read

What we know so far about Omicron subvariant BA.2

What we know so far about Omicron subvariant BA.2
Back to Alert Level 2 soon?

Pandemic officials are optimistic that Metro Manila could be downgraded to Alert Level 2 again if the downward trend in cases is sustained. Across the country, however, other regions have not yet seen the worst of Omicron.

  • Health Secretary Francisco Duque III said that for this to happen, NCR should be at moderate risk for the virus while the health utilization rate should be at low risk based on bed occupancy. 
    • The government’s coronavirus task force will take up the matter on Thursday, January 27.
    • While cases have been on the downtrend, the average number of cases reported in the recent week tallied about 10,198, almost double the average number of weekly cases of 5,926 seen during Delta’s peak. As cases decreased back then, experts warned that opening up too early, even as thousands of cases continued to be logged daily, could reverse the sacrifices people made. 
  • Although less severe compared to Delta, Omicron is still placing immense strain on our health systems. The DOH said hospitalizations were up nationally by 4%, with admissions climbing from 49% to 52% in the recent week. 
    • A “decoupling” where the increase in cases did not result to the same increase in hospitalizations was still seen in Metro Manila, thanks to vaccines. But admission is still high – if during the Delta surge, an average of 8,680 cases needed hospital care per week, some 6,523 admissions were reported on average under Omicron. 
    • Other regions with lower vaccination rates could see hospitals hit harder by the rapid increase in infections.
    • While cases have been decreasing, hospitalization trends usually lag behind infections. 
Findings clues in sewage

Omicron’s swift sweep across the world has placed renewed focus on testing capacities of different countries. With access to tests and turnover of results struggling to keep up with the pace of the virus’ spread, some counties have tried to find answers in wastewater testing.

  • How can sewage fill testing gaps? “People who contract the coronavirus shed the virus in their stool, and the virus levels in local wastewater provide a strong, independent signal of how much is circulating in a given community,” the New York Times reported. 
    • In areas where wastewater testing was robust, findings were used to inform local responses to the pandemic. For instance, “City officials are using it to funnel resources into neighborhoods where the virus is surging, and hospitals are using it to make life-or-death decisions about which treatments to administer,” the New York Times said.
    • Wastewater samples can also offer clues as to suggest when a virus is starting to emerge or may have peaked in certain areas. 
  • In the Philippines, wastewater testing is usually done to monitor polio in different communities. But the country lacks the sewage infrastructure that could lend detailed insight to how the virus is behaving at a more precise, community level. 
    • Epidemiologist Dr. John Wong of the Ateneo School of Public Health told us that locally one problem of wastewater epidemiology is very few houses and buildings were actually connected to the sewage system. This leaves officials with big bodies of water like Pasig River or Manila Bay for sampling. 
    • The downside? “They can’t pinpoint the source of the virus which is one of the benefits of wastewater epidemiology,” Wong said. 
    • Still, it’s not all useless: “It will be decades before we can do it with precision. For now, the most we can do is to use it to predict trends for the whole metropolis,” he added. 
  • And, after  that, “interpreting results and acting on them is the key,” former health secretary Manuel Dayrit told us. 
  • Looking ahead, the Department of Health also said that, with the  Research Institute for Tropical Medicine (RITM) and the support of the World Health Organization (WHO), seven subnational laboratories will be established in the country to detect vaccine-preventable diseases.

In case you missed it: Vaccinations will soon open to kids aged 5 to 11 on February 4. Only Pfizer’s vaccine – with a slightly lower dosage and concentration – has been cleared for emergency use among the 15.56 million kids in this age group. 

The DOH said that parents can already enlist their children for vaccination in their respective local government units. Catch up here:

Must Read

PH gov’t targets COVID-19 vaccination for kids aged 5 to 11 on February 4

PH gov’t targets COVID-19 vaccination for kids aged 5 to 11 on February 4

– Rappler.com

Sofia Tomacruz

Sofia Tomacruz covers foreign affairs and is the lead reporter on the coronavirus pandemic. She also writes stories on the treatment of women and children. Follow her on Twitter via @sofiatomacruz. Email her at sofia.tomacruz@rappler.com.