How Technology Accelerated Singapore’s COVID-19 Vaccination Rollout

Behind the scenes of how Open Government Products used technology to enable COVID-19 vaccinations in Singapore

Chan Chi Ling, Deputy Director and Head of Ops-Tech

Kevan Tan, Software Engineer

Sarah Espaldon, Marketing & Operations Manager


In late December 2020, Singapore commenced its first nation-wide vaccination rollout of the COVID-19 vaccine. Amidst vaccine supply uncertainty, there was a need to match supply and demand of vaccines for different population segments with precision across more than 80 vaccination centres island-wide. As this was a vaccination exercise of unprecedented scale for Singapore that needed to be accomplished within a short time, OGP served as MOH’s tech partner to rapidly build and deploy a suite of systems to support vaccination operations.

To date, our vaccination systems have facilitated over 6.8 million doses of the COVID-19 vaccine, and more than 2.8 million people have completed the full vaccination regimen. In this blog post, we go behind-the-scenes to uncover the tech systems supporting Singapore’s COVID-19 vaccination programme.

The Challenge

When OGP first joined the project in late December 2020, we identified 8 key challenges in building systems for the vaccination rollout:

  1. Prioritisation. Given the limited availability of the vaccine, we needed a way to phase in different segments of the population based on an order of priority;
  2. Ease of use. Not everyone booking vaccines would be digitally savvy, and one of our first priority groups was seniors. We needed a seamless and inclusive user experience that would encourage users of all ages to book;
  3. Accessibility and trust. Vaccination appointments needed to be accessible through trusted systems, users need to secure slots within a reasonable timeframe, and long waiting times on-site were to be avoided;
  4. Reliability. Given the high volume anticipated, any solution would need to withstand exceptionally high traffic, and system uptime would be critical for vaccine throughput;
  5. Throughput. To maximise throughput (i.e. the number of people receiving vaccines given available supply), we needed to maximise registrations and turn-out, and minimise no-shows;
  6. Accuracy of records. We needed consistent record-keeping of who had been vaccinated, with what brand of the vaccine, and its effective date.
  7. Integration. Various upstream and downstream systems need to retrieve vaccination records in real-time;
  8. Decision support. High-resolution and real-time data would be needed for decision support and operational awareness.

What we built

Time was of the essence. The team needed to understand key operational needs, design a user experience that would maximise the number of people receiving vaccines, and then build it — all within two weeks. Project requirements were evolving rapidly, which meant that whatever we built had to be flexible and responsive to our changing operational environment.

In a two-week sprint, and refined over subsequent months, the team built a suite of vaccine operations systems, consisting of six components:

  1. Pre-registration systemAn online FormSG form where members of the public can pre-register to be notified via SMS when their turn arrives to schedule appointments. This helps to titrate in demand based on different priority groups and vaccine availability. Every pre-registration is authenticated.
Pre-registration FormSG form.

2. National Appointment System (NAS) — When it becomes their turn to book appointments, users are sent a unique booking link to book appointments for both doses of the vaccine. The NAS does a few things — it:

  • Authenticates the patient
  • Conducts a demographic and medical triage to ascertain that patient is medically fit to be administered the vaccine, and collects informed consent
  • Directs the patient to secure two doses, at least 21 days apart, at their preferred vaccination site and preferred time slots
  • Shows which clinics have more slots available, to optimise matching of demand and supply
  • Sends a confirmation SMS with appointment details once both appointments are secured
  • Sends appointment reminders via SMS to reduce no-show rates
  • Enables patients to cancel or reschedule their appointments
Landing page of

3. Proxy booking system — To ensure that less digitally savvy segments of the population can also access vaccines easily, we built a proxy booking system used by volunteers from People’s Association and Silver Generation Office to book appointments for seniors at Community Centres, or via house visits.

4. Clinic administration system — A clinic administration system is deployed across all 80 vaccination centres, polyclinics, and public health preparedness clinics (PHPCs) for tracking of daily appointments, patient rescheduling, and registration of walk-in patients. This enables vaccination centres to plan ahead for logistics and resupply, and helps patients without prior appointments to secure appointment slots for their second dose at point of a walk-in appointment (currently available for seniors).

Clinic administration system at a vaccination centre.

5. Vaccination records — Once the vaccination has been completed, records are validated to ensure that data is consistent, complete, and securely stored. Business logic is applied on these records to derive an accurate vaccination status. Downstream systems such as TraceTogether, Notarise, and HealthHub are therefore able to pull vaccination statuses for display on their frontends.

6. Command-and-Control (C2) system — For a complex mission with many moving parts, decisions need to be guided by timely data. To enable data analysts and policymakers to monitor take-up across population segments and vaccination sites, we built a C2 system to provide an accurate and real-time read of the ground situation, and to better optimise demand and supply for vaccines.

What we learned (and what worked)

To maximise throughput, or the number of people receiving vaccines, we needed a trusted, frictionless user experience that would encourage all residents to book appointments, regardless of their age and digital savviness. In the process, we learned that details matter (a ton!) to accelerating the rate of vaccination, because how our systems mobilise patients, direct them to book the earliest possible slots, and remind them to show up directly impacts our rate of vaccination.

There were 3 key design decisions that helped to accelerate our vaccination throughput:

Pre-registration for demand calibration

In theory, a rudimentary vaccination system needed to simply allow people to book time slots for their vaccination appointments — a task that could have easily been implemented with existing, off-the-shelf solutions. However, the COVID-19 vaccination rollout, with the variability in both vaccine supply and user demand, necessitated a solution that could give MOH better control over demand. One tool that helped us to better respond to fluctuations in supply and demand was the pre-registration step.

In maximising throughput (i.e. the number of people receiving vaccines given available supply), there were two key uncertainties: vaccine supply and population demand. Absent perfect information on either element, pre-registration allowed us to titrate demand based on actual supply of vaccination slots. With every arrival of new vaccine supply, a new batch of pre-registered individuals would be activated via SMS to book their appointments. Pre-registration worked like a rate-limiter for the vaccination system, allowing us to calibrate the rate at which we phase in demand into the appointment system based on the supply we have.

Inclusive and frictionless user experience

One of the unique challenges of a national vaccination programme aimed at achieving herd immunity was that the user base was not confined: it was everybody. How might we design a process that made vaccine appointments accessible to everybody, regardless of age and digital savviness? We quickly realised that there was no one-size-fits-all solution. To be inclusive, we needed targeted solutions for users of different demographic profiles.

For the majority of digitally-savvy users with a smartphone, we created a mobile-responsive appointment booking system that helped users to authenticate identity, book appointments, complete declarations and medical triage, and reschedule appointments in a frictionless way. To maximise turn-out, we enabled users to select both preferred locations and available time slots, and sent them SMS reminders prior to their appointments.

For some segments of our senior population who could not book online without assistance, we built a proxy booking system that enabled volunteers from People’s Association and Silver Generation Office to book appointments for them. With the proxy booking system, volunteers were able to go door-to-door with their smartphones or iPads and help seniors secure their appointments within minutes. This helped to accelerate the vaccination of our senior population — as of July 2021, more than 85% of those between 60–69 had received two vaccine doses.

Loosely coupled components for improved reliability

Reliability was top of mind for the team since Day 1. For a nation-wide rollout, any uncaught bugs in application logic or unresolved issues in our technical infrastructure could cause large-scale ripple effects or severe disruptions to the entire vaccination programme. Given a timeframe of weeks to build the system, we managed risks by designing loosely coupled components rather than a system that stood as a monolithic block. The idea was to de-construct a complex end-to-end process into individual components that were highly aligned but loosely coupled — this included pre-registration, appointments self-booking, proxy booking, clinic administration, decision support, and vaccination records.

From a product management perspective, breaking a large product team into smaller teams concentrating on specific parts of the system lent focus and helped us move faster. From a technical risk management perspective, this did two things: 1) it helped us trace bugs to its source more easily and quickly and 2) it allowed other parts of the system to continue operating without major interference should one part of the system experience downtime. An unexpected benefit of this modularity was that we could swap out parts of our system for ground flexibility — for example, vaccination centres could use a different clinic system for recording vaccination information and still call our systems’ API endpoints to update results. It also enabled other ministries with varying operational needs to tailor their appointment workflows, and plug and play into the national appointment system without the need for major technical changes.

Finally, we should point out that all these systems were developed in close collaboration with our MOH counterparts, who had been instrumental in pulling together the whole vaccination operation. As their technology partner, OGP worked closely with MOH to design and build systems to serve this critical nationwide programme. Especially amidst an ever-changing situation, this collaboration would not have been possible without both operational and technical teams working closely together in this joint mission. Many thanks to the public officers across agencies, volunteers, and healthcare professionals for the tremendous work behind this national effort!

The vaccination programme is one of the many public sector tech challenges we work on as Open Government Products. We’re building a community — of designers, engineers, product managers, and more — who want to build technology for public good. If working on these problems appeals to you, we’re hiring! Apply at or ping us on our socials to chat about what life is like at OGP.

Product Team



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