Experts Say 80% of People in S’pore Must Be Vaccinated for Herd Immunity


With the recent announcement of Pfizer-BioNTech vaccine in Singapore, herd immunity against Covid-19 is now possible.

But how many people should be vaccinated before we can achieve the coveted herd immunity?

The golden number: 80%.

According to the Health Ministry’s chief health scientist, Professor Tan Chorh Chuan, herd immunity indirectly reduces the risk of Covid-19 for those who are not immune to it. He also added that the estimates for herd immunity generally vary around 60 to 70%. However, a vaccine coverage of 80% will be sufficient.

If we assume that the efficacy of the vaccine is 90%, and 80% of the community is vaccinated, 72% of the population will become protected.

Should you get vaccinated? Professor Tan highly encourages it if you’re suitable to have it. It will not only protect you, but will also protect your family members and those in close contact with you.

And we can achieve herd immunity sooner, which means we’d have defeated COVID-19.


Current Situation

When the vaccines arrive in Singapore, healthcare and frontline workers, as well as elderly and vulnerable patients will be given priority in accessing these vaccines. Elderly people will include those aged 60 and above.

By the third quarter of 2021, there will be enough vaccines for everyone else, and getting vaccinated will be free for all Singaporeans.

But getting vaccinated isn’t compulsory, so getting the 80% isn’t a certainty by next year.

As there are close to a million people who fall under the elderly group, they are currently planning on how to roll out the vaccines. They will likely be prioritising elderly people in institutional care settings, such as nursing homes.

Professor Tan also mentioned that if elderly and those suffering from multiple health problems are vaccinated, infection rates would fall among these groups.

Healthcare and frontline workers will be given priority to protect them from the virus as they are in contact with many people daily. This will also reduce the risk of healthcare services being impacted if there is a sudden surge of infections among healthcare workers.

Frontline workers include non-medical staff at medical institutions, quarantine operations and those working at the borders.

Achieving Herd Immunity

When herd immunity is achieved, individuals are also helping to protect those who are unable to be vaccinated because of age or medical restrictions.

This includes pregnant women and people who suffer from extreme allergic reactions.

On 10 December, it was reported that Britain had warned people suffering from anaphylaxis to avoid getting vaccinated. Anaphylaxis is an overreaction of the body’s immune system. It can be caused by almost anything, including food, insect bites, medications and latex.

Anaphylaxis can also be fatal.

It was also reported that elderly people experienced the similar side effects as younger adults. This included pain at the injection site, headaches, tiredness and fevers. Professor Tan also added that these side effects were less common and milder compared to a younger person’s experience of it.

In November, Pfizer Inc announced that they had concluded their third trial of the vaccines with a 95% efficacy. Those aged 65 and above saw over 94% efficacy.

While this is good news, he is unsure if the vaccines also reduce and block viral transmissions of the virus, though this was reflected in animal studies.


Even if people are vaccinated, they should continue to wear masks and continue to adhere to safe distancing measures.

Featured Image: Siti Nur Sahira /

Fresh grads, you don’t need any experience to earn up to $4,200 with this “secret”:

Read Also: