Using a mathematical model, researchers at Harvard T.H. Chan School of Public Health found that a Delta-like variant of the coronavirus is most likely to cause a more severe pandemic, according to Medical Xpress.

The strain similar to Delta has enhanced transmissibility and an ability to infect people who had previous infections or vaccination, which can result in breakthrough infections/reinfections.

The researchers published their paper online in Cell. They said the discovery could help public health officials understand the significance of the novel and existing strain and develop tailored public health responses for various scenarios based on a variant’s characteristics, per Medical Xpress.

The paper’s co-author Mary Bushman said, “Thus far, evidence of immune escape – the ability of a variant to evade the immune system and cause reinfections or breakthrough infections—has been a red flag. Our findings say it’s maybe more of a yellow flag – this is not such a big deal on its own. But when it’s combined with enhanced transmissibility, then it can be a really big deal.”

Some variants of SARS-CoV-2 have quickly become a dominant strain, increasing the number of infections, such as the Alpha (discovered in the UK) and Delta (discovered in India) variants. However, others variants, such as Beta (discovered in South Africa), failed to take hold.

Bushman created a mathematical model that simulates how pandemics fueled by hypothetical variants would affect populations. The analysis simulated a COVID-19 pandemic with several different hypothetical strains.

Bushman and her team determined that a variant with enhanced transmissibility and the ability to re-infect people with previous infections or vaccinations could be more dangerous.

The model also predicted that vaccination is highly beneficial if Delta-like variants become dominant. The researchers found that vaccinations would prevent a greater number of cases caused by a more transmissible virus.

The paper’s other co-author Bill Hanage said, “It’s really important that people realize the emergence of variants like Delta make high levels of vaccination all the more crucial.”

“Even if we cannot eliminate the virus, we can ensure that people face it with the best preparation, and a more transmissible virus means there will be more infections in the absence of vaccination, so more people stand to benefit from it,” he added.