Jakarta Health Agency head Widyastuti said at a press briefing on Jan. 14 that the city aimed to vaccinate 7.9 million people to achieve herd immunity. "It's our largest vaccination drive. Our previous mass vaccination program was only designed [to inoculate] 2 million people," said Widyastudi, without indicating the year or the targeted disease of the previous program.

Based on the official population of 10.5 million, this works out to 75.2 percent of Jakartans getting the jab.

An article published on Johns Hopkins’ COVID-19: School of Public Health Expert Insights states: “Depending how contagious an infection is, usually 50% to 90% of a population needs immunity to achieve herd immunity”. Meanwhile, the World Health Organization (WHO) has maintained that “The proportion of the population that must be vaccinated against COVID-19 to begin inducing herd immunity is not known.”

Read also: 'Long road' to herd immunity even with COVID-19 vaccination

The first stage of Jakarta’s COVID-19 vaccination program commenced on Thursday, with health authorities aiming to inoculate 60,000 health workers and a handful of public officials.

“We received 120,040 doses of the COVID-19 vaccine from state-owned pharmaceutical firm PT Bio Farma on Jan. 11,” said Widyastuti.

The current vaccine supply still fell short of the doses needed to cover all 131,000 of the city’s health workers, she acknowledged, but the agency was focusing on ensuring that one person would receive the required two doses of the vaccine within 14 days.

Apart from health workers, 21 public officials are scheduled to be inoculated on Friday, including Jakarta provincial secretary Marullah Matali and the mayors of all capital districts.

Governor Anies Baswedan and Deputy Governor Ahmad Riza Patria, however, are not on the list of first-stage recipients, as they had already contracted and recovered from the disease, and would therefore have natural antibodies.

Indonesia started the first stage of its nationwide COVID-19 vaccination drive on Wednesday, when President Joko Widodo became the first person in the country to be inoculated.

In the first stage of the mass vaccination program, the country is using the CoronaVac vaccine developed by China’s Sinovac Biotech. Bio Farm’s late-stage clinical trials in Bandung, West Java, showed a 65.3 percent efficacy rate in interim results.

Meanwhile, a separate CoronaVac trial in Brazil that involved volunteers with “very mild” to “severe” cases reported an efficacy rate of just 50.4 percent.

The figure is relatively low compared to two other vaccines that have received emergency use authorization (EUA) in the United States. The vaccine developed by Germany’s Pfizer and the US’ BioNTech reported an interim result of 95 percent efficacy, while the vaccine developed by US biotech Moderna was confirmed to be 94.1 percent effective in a peer-reviewed study.

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On Monday, Indonesia’s Food and Drug Monitoring Agency (BPOM) granted the EUA for CoronaVac, becoming the first country outside China to approve its use. The Indonesian Ulema Council (MUI) has also issued a fatwa that declares the Chinese vaccine as halal and safe to use for Muslims.

The country has procured 18 million doses of CoronaVac, with the latest consignment landing in Jakarta on Tuesday.

Widyastuti said the city health agency had finished distributing 120,040 doses of the vaccine to more than 400 health facilities in the capital, including to 266 puskesmas (community health centers). It had also trained around 1,400 health workers how to give a jab.

She added that the vaccination program would be monitored by the Jakarta branch of the National Committee for the Assessment and Control of Post-Immunization Adverse Events (Komnas PP KIPI), which had designated 21 hospitals to treat any adverse reactions to the COVID-19 vaccine.

Read also: Hospitals, cemeteries overwhelmed as Jakarta faces new spike in COVID-19 cases

The vaccine drive commences amid the continuing surge in new COVID-19 cases in the capital, especially following the year-end holiday season. Jakarta has seen record numbers of daily cases over the past two weeks, recording its latest daily high of 3,476 new cases on Wednesday.

Jakarta’s COVID-19 website on Friday showed 220,434 total cases, including 20,800 active cases and 3,710 total deaths.

Health facilities in the capital are overwhelmed with the bed occupancy rate averaging over 80 percent for intensive care units (ICU) equipped with ventilators and isolation rooms. Plots are also running out at cemeteries designated for COVID-19 burials, which has forced some to adopt a double-depth burial space policy.