How effective should a Covid-19 vaccine be for the world to turn 'back to normal'?

  • Vaccines for Covid-19 are being developed, but not all vaccines work the same way
  • A new computational simulation model calculated the scenarios based on different vaccine efficacies
  • For the pandemic to be halted, a high-efficacy vaccine needs to be given to a large part of the population

As the Covid-19 pandemic continues, researchers are working tirelessly to develop a vaccine.

Currently, 16 vaccines have already reached clinical phases, while more than 100 are in the immunisation pipeline. But how effective does a vaccine need to be in order for the world to safely "open up" again?

Scenarios analysed with models

The new study, published in the American Journal of Preventive Medicine, made use of various modelled scenarios and sensitivity analyses to evaluate the impact of introducing vaccines with different efficacies without the implementation of other measures.

The model found that if 75% of the population got vaccinated, the vaccine would have to have an efficacy (ability to protect against infection) of at least 70% to prevent an epidemic, and at least 80% to extinguish an ongoing epidemic.

If only 60% of the population got vaccinated, the thresholds would be even higher, i.e. around 80% to prevent an epidemic and 100% to extinguish an ongoing epidemic, according to a news release.

Expectations need to be managed

While there is optimism about a possible vaccine, it’s also crucial to understand the process and to know what a vaccine needs to deliver to truly manage the pandemic.

Lead investigator Bruce Y. Lee, MD (MBA, Public Health Informatics, Computational and Operations Research, CUNY Graduate School of Public Health and Health Policy, New York, NY, USA) stated in the news release that expectations around vaccines need to be managed.

"Some are pushing for a vaccine to come out as quickly as possible so that life can 'return to normal'. However, we have to set appropriate expectations. Just because a vaccine comes out doesn't mean you can go back to life as it was before the pandemic," Lee said.

"It is important to remember that a vaccine is like many other products – what matters is not just that a product is available, but also how effective it is."

READ | Yet another study finds vaccines to be safe 

READ | SA to take part in two more Covid-19 trials 

READ | Oxford trial step in right direction, but challenges still ahead

Image credit: iStock

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