Herd Immunity to COVID-19 Likely Will Not Be Achieved in 2021, Experts Suggest

Herd Immunity Concept

The advancing rollout of currently approved coronavirus disease 2019 (COVID-19) vaccines provides hope to many that existing lockdowns and social restrictions will soon be lifted, but experts suggest a “return to normal” likely won’t occur until herd immunity is achieved.

Speaking to the Reuters Next conference, Dale Fisher, chairman of the World Health Organization's (WHO) Outbreak Alert and Response Network, said that achievement of herd immunity in most countries is unlikely in 2021.

"There might be some countries that might achieve it but even then, that will not create 'normal' especially in terms of border controls," he added.

Approximately 90 million across the globe have reportedly been infected by SAR-CoV-2, the novel coronavirus responsible for COVID-19. In addition, around 1.9 million people with COVID-19 have died as a result of the infection since the onset of the pandemic.

Some COVID-19 vaccines have been approved for emergency use to curtail the rising tide of infections and COVID-19-related deaths across the world. These vaccines include those developed by Moderna, AstraZeneca and Oxford University as well as by Pfizer and its development partner BioNTech. CureVac's COVID-19 vaccine candidate, CVnCoV, has also shown promise for future approval, but more robust late-stage trial data are needed before the vaccine can be considered for ultimate approval.

According to Fisher, these vaccines will probably help quell mass community transmission, but this will only be the first step toward achieving herd immunity in some regions. And once herd immunity is achieved, Fisher suggests COVID-19 will be here to stay. “It can be controlled, but I still think, forevermore, there'll still be cases,” he said. “But if we can control it with vaccine, then we'll be limiting that community, that mass spread that we're seeing.”

Fisher adds that during the vaccine rollout, many countries will see “easing of restrictions,” but many countries are still “a long way away” from this.

Plus, noted Fisher, scientists still do not know everything about the approved COVID-19 vaccines, including their long-term efficacy profiles. “We can be very confident it's safe,” he said. “We can be very confident that it's effective in the short term. But if this all wears off after six or 12 months, then there's going to be new problems arise. So we still have a lot to learn about what the future looks like.”

Last week, Moderna CEO Stephane Bancel said the protection from his company’s COVID-19 vaccine could be expected to last for years, despite the lack of long-term immune memory data for the vaccine.

A recent study in Science found that many patients with COVID-19 have a long-lasting immunity to the SARS-CoV-2 virus as well as a durable immune response up to eight months after the initial symptoms onset. Whether or not these findings can be generalized to vaccine exposure remains undetermined.

Echoing Fisher’s statements, Francesco Rocca, President of the International Federation of Red Cross and Red Crescent Societies (IFRC), recently noted in a press release that vaccines alone won’t be responsible for ending the COVID-19 pandemic. “We all need to make sure that, in our optimism about vaccines, we do not forget the dangers of this virus or the actions we all need to take to protect ourselves and each other,” said Rocca. “COVID-19 is still killing thousands of people every single day. We each have a responsibility to stay vigilant and to practice the preventative measures that will curb the spread.”

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