Authorities and experts believe the phenomenon can partly be attributed to a false sense of security following the vaccine rollout that has led many office workers to lower their compliance with health rules.

The Jakarta Health Agency found at least 157 confirmed COVID-19 cases in 78 office spaces across Indonesia's capital from April 5 to 11. The figure almost tripled the following week, with the agency reporting 425 new cases from 177 workplace-related clusters.

Last week, infections among office workers dropped to 68 cases, but agency head Widyastuti warned the public that without full compliance with health protocols the number might rise again.

At least 324 office workers that contracted COVID-19 last month have been vaccinated, according to the agency's data cited by Pandu Riono, an epidemiologist from the University of Indonesia who works closely with the Jakarta COVID-19 task force.

The Jakarta administration started the vaccination drive for essential workers on Feb. 17, aiming to inoculate 1.97 million workers in the city by the end of this month. By Monday, around 1.23 million workers had received their first jab, with only about 676,000 of them having received their second dose.

Read also: Jakarta aims for 75.2% coverage in 'massive' COVID-19 vaccination drive amid 2-week spike

Pandu said people tended to lower their guard against the virus as they developed a false sense of safety after completing the two-dose vaccine regimen. He criticized the central government for failing to educate the public that vaccination would not 100 percent protect people from catching the virus.

"Vaccination does not necessarily protect us from being infected and from infecting others. It only reduces the severity of the symptoms when we contract the virus," Pandu told The Jakarta Post on Monday.

Of the 324 office workers who contracted the coronavirus after getting the COVID-19 shots, only 6 percent required hospitalization and all of them made a full recovery. Meanwhile, 73 percent others showed mild symptoms and the remaining 21 percent showed no symptoms.

Data compiled by the Jakarta Manpower, Transmigration and Energy Agency showed that from Jan. 11 to April 23, at least 2,100 office buildings in the capital city were temporarily closed either due to COVID-19 transmission on their premises or health protocol violations.

The agency, however, says it does not have enough manpower to constantly monitor how office management and their workers apply health rules in the workplace.

“We only have 59 monitoring officers in the field and our agency is currently focusing on resolving many mass layoff cases and delayed holiday bonuses [THR] ahead of the coming Idul Fitri holidays [in mid-May],” agency head Andri Yansyah told kompas.com last week.

The health agency’s Widyastuti advised companies to require 50 percent of their employees to work remotely, in line with the rule under the existing micro-scale public activity restrictions (PPKM Mikro) in Jakarta.

However, in reality a lot of workplaces, especially those whose essential workers have already been vaccinated, are operating at full capacity.

“We need to make it clear that those who have been vaccinated are not 100 percent free from the risk of contracting COVID-19. So, enforcing consistent and stricter health protocols in office buildings is indispensable,” she said on Friday.

Read also: Yes, COVID-19 figures in Jakarta have dropped. But the public must remain alert

She said the public must act and report any health rule violations to authorities via the city-owned mobile application Jakarta Kini (JAKI).

Pandu also suspected the urge to socially interact during Ramadan might also be another reason why people compromised their health.

“People tend to meet each other more during Ramadan. Many office workers, for example, usually often attend breaking-of-the-fast gatherings in public places, which might increase the risk of COVID-19 transmission,” he said.

This year, Muslims in Indonesia are observing the second Ramadan during the COVID-19 pandemic under more relaxed restrictions than last year, following a drop in confirmed cases and the gradual rollout of vaccines. Unlike last year, the central government permits mosques to remain open at half capacity during Ramadan with mandatory physical distancing and mask wearing. It allows people to hold breaking-of-the-fast gatherings at public places at 50 percent of capacity.

Read also: Jakarta Muslims enjoy relaxed rules in second Ramadan during pandemic

But following the surge in infections among office workers in Jakarta, Governor Anies Baswedan banned city officials from hosting breaking-of-the-fast gatherings starting last week and urged Jakartans to avoid gatherings.

The number of daily COVID-19 cases in Jakarta has decreased since January, when it recorded daily highs of over 3,700 cases, to an average of 1,070 in the week of March 28 to April 3, and 830 in the following week just after the long Easter weekend. The daily figures increased again to an average of 930 cases and 860 cases in the second and third week of April before decreasing to an average of 760 cases in the last week of April and early May.

On Tuesday, Jakarta recorded 416 new cases, bringing the total tally to 411,573 cases since COVID-19 hit the city last year.