WHO: COVID-19 herd immunity unlikely in 2021 despite vaccines
The World Health Organization's chief scientist warned that even as numerous countries have started rolling out vaccination programs to stop COVID-19, herd immunity is highly unlikely this year. At a media briefing on Monday, Dr. Soumya Swaminathan said it was critical that countries and their populations maintain strict social distancing and other outbreak control measures for the foreseeable future.
'Herd immunity not going to protect people across the world'
Britain, the US, France, Canada, Germany, Israel, the Netherlands, and others have already begun vaccinating millions of their citizens. "Even as vaccines start protecting the most vulnerable, we're not going to achieve any levels of population immunity or herd immunity in 2021," Swaminathan said. She added that it's not going to protect people across the world even if it happens in a few countries.
Why is it difficult to achieve herd immunity?
For an entire population to be protected, a vaccination rate of about 70% is typically required, scientists estimate. But some fear that the extremely infectious nature of COVID-19 could require a significantly higher threshold. Further, Dr. Bruce Aylward, an advisor to WHO's Director-General, said the UN health agency is hoping that coronavirus vaccinations begin by February in some of the world's poorer countries.
WHO aiming at a 'roll-out plan' for developing countries
Aylward said, WHO was aiming to have "a roll-out plan" detailing which developing countries might start receiving vaccines next month. However, he called for the global community to do more to ensure all countries have access to vaccines. "We cannot do that on our own," Aylward said, adding that WHO needed the cooperation of vaccine manufacturers, in particular, to start immunizing vulnerable populations.
COVAX faces shortage of logistical help from donor countries
Notably, the majority of the world's COVID-19 vaccine supply has already been bought by rich countries. The UN-backed initiative COVAX, which is aiming to deliver shots to developing countries, is short of vaccines, money and logistical help as donor countries scramble to protect their own citizens, particularly in the wake of newly detected COVID-19 variants, which many officials are blaming for increased spread.
Case spike was detected before the new variant's detection
WHO, however, said that "the increased mixing of people" caused most of the recent spikes in transmission. WHO's technical lead on COVID-19, Maria Van Kerkhove said that the spike in cases in numerous countries was detected before the new variants were identified, and noted that during the summer, COVID-19 cases were down to single digits in most countries across Europe.
Holidays majorly responsible for the rise in numbers
"We lost the battle because we changed our mixing patterns over the summer, into the fall and especially around Christmas and the new year," Van Kerkhove said, explaining that people had multiple contacts with family and friends over the holidays, leading to rise in numbers.
No evidence that variants are driving any element of severity
Dr. Michael Ryan, WHO's Executive Director of Health Emergencies Programme, said, while there is some evidence that variants may be speeding the spread of COVID-19, "there is no evidence that variants are driving any element of severity." He said the variants shouldn't alter countries' strategies for controlling outbreaks. "It doesn't change what you do, but it gives the virus some new energy," Ryan said.
