MANILA, Philippines – Part of the premise of easing community quarantine in much of the country is that certain areas can be placed on lockdown if they register a spike in COVID-19 cases.

This way, the government hopes to contain the coronavirus without unnecessarily halting economic activity. The National Task Force (NTF) against COVID-19 calls this a “zoning containment strategy.”

A set of operational guidelines from the NTF released on June 15 describes how the government implements these localized lockdowns.

‘Cluster of cases’

The strategy hinges on identifying “clusters of cases” in a certain location.

The NTF defines a “cluster of cases” as two or more suspected, probable, or confirmed COVID-19 cases in the same area at the same time, or within the past 7 days.

Depending on the occurrence of “clusters of cases,” an area such as a house, building, street, village, or city can be declared a “critical zone” in and around which strict lockdowns may be imposed.

Critical zones

Once the local or national government declares an area a “critical zone,” it is placed in enhanced community quarantine (ECQ) – or lockdown – regardless of what community quarantine measure is enforced in the broader area where it is located.

House – A house becomes a critical zone if it has at least one suspect, probable, or confirmed COVID-19 case.

Residential building – If there is a cluster of cases in a residential building, the entire building becomes a critical zone. If contact tracing finds the cases are limited to a single floor, then only that floor will be considered a critical zone.

Business or work establishment 

• A small business or work establishment with less than 1,000 occupants becomes a critical zone if it has at least one cluster of cases involving occupants who visited the premises within the last 14 days.
• A large business or work establishment with 1,000 or more occupants becomes a critical zone if it has at least two clusters of cases involving occupants who visited different parts of the premises within the last 14 days.

Market – A market, supermarket, or commercial center becomes a critical zone if there are at least 3 clusters of cases in the barangay where it is located.

Street – A street becomes a critical zone if there are at least two clusters of cases among different houses, buildings or establishments on it. This excludes national highways.

Block – A block becomes a critical zone if there are at least 3 clusters of cases among at least two different streets surrounding it.

Purok – A purok becomes a critical zone if there are at least 3 clusters of cases among different houses or buildings within it.

Subdivision or village – A subdivision or village becomes a critical zone if there are at least 4 clusters of cases among at least two streets or blocks within it.

Barangay

• A densely populated barangay with more than 1,000 people per square kilometer becomes a critical zone if there are at least 5 clusters of cases among at least 3 sitios, puroks, or blocks within it.
• A sparsely populated barangay with less than 1,000 people per square kilometer becomes a critical zone if there are at least two clusters of cases among at least two sitios, puroks, or blocks within it.

City or municipality – An entire city or municipality becomes a critical zone if at least 25% of its barangays are declared critical zones, “with causal link to areas reserved and occupied as residential and/or commercial corridors, and population density is greater than 1,000 per square kilometer,” per the NTF guidelines.

Clustered critical zone – If a place is sandwiched between two critical zones, then it also becomes a critical zone. The government will then treat the area as a “clustered critical zone.”

Containment zone, buffer zone

Like concentric circles, layers of containment are established around a critical zone, each one less restrictive the farther it is from ground zero:

Containment zone – an area without case clusters but is adjacent to a critical zone. It is placed under modified enhanced community quarantine (MECQ).

Buffer zone – an area without case clusters, adjacent to a containment zone. It is placed under general community quarantine (GCQ).

Areas outside buffer zone – These are all areas outside critical, containment, or buffer zones. As with the rest of the country, these areas are under modified general community quarantine (MGCQ).

How are containment and buffer zones identified?

Containment zone

• If the critical zone is a house, building, business establishment, market, street, or subdivision, the containment zone is the 500-meter radius around the critical zone.
• If the critical zone is a purok, barangay, city or municipality, the containment zone is the equivalent geographical unit along its border. For example, if a barangay is a critical zone, then all barangays immediately around it are its containment zone.

Buffer zone

• If the critical zone is a house, building, business establishment, market, street, or subdivision, the buffer zone is the 500-meter radius around the containment zone.
• If the critical zone is a purok, barangay, city or municipality, the buffer zone consists of the equivalent geographical units around the containment zone. For example, if a barangay is a critical zone, and its containment zone consists of all the barangays immediately around it, the barangays next to the containment zone are the buffer zone.

If an area such as a house, building, subdivision, purok, or barangay only partially falls within the 500-meter radius of a critical zone, the entire place becomes part of its containment zone.

If such an area lies between a containment or buffer zone, it is considered part of the area under stricter quarantine, i.e., the containment zone.

What for, and for how long? 

The point in enforcing zonal lockdowns is to focus efforts such as contact tracing and expanded coronavirus testing on critical zones.

Local governments are supposed to have a local task force ideally composed of separate teams for contact tracing, testing, patient management and monitoring, as well as logistics and resource support.

The local task force is supposed to go into the critical zone for aggressive contact tracing and testing of people who have had contact with the suspected, probable, and confirmed COVID-19 cases.

They must also ensure a steady supply of food, water, and other necessities for the people inside the critical zone, as well as the containment and buffer zones.

The local task force is to reassess the situation very 15th and 30th of the month. When all cases have tested negative, no new cases are identified, and the people within the critical zone have completed a 14-day quarantine period, then the zonal lockdown can be lifted.

As of Sunday, June 21, there were 113 localized or zonal lockdowns imposed across the country, including 8 cities and municipalities, 71 barangays, 16 sitios, a subdivision, 9 “zones,” 6 streets, and two buildings. – Rappler.com