The chief scientist of the World Health Organization cautioned that even as various nations start carrying out vaccination campaigns to stop Covid-19, herd immunity is highly unlikely this year.
At a media briefing on Monday, Dr. Soumya Swaminathan said it was critical countries and their populations maintain strict social distancing and other outbreak control measures for the foreseeable future.
United Kingdom, United States, France, Canada, Germany, Israel, the Netherlands, and others have started vaccinating millions of their people against coronavirus in recent weeks.
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“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.
“Even if it happens in a couple of pockets, in a few countries, it’s not going to protect people across the world.”
70% vaccination rate is needed for herd immunity
Scientists generally estimate that for herd immunity, where whole populations are protected against a disease, a vaccination rate of about 70 percent is required. But some fear that a significantly higher threshold may be needed for the extremely infectious nature of Covid-19.
Dr. Bruce Aylward, WHO Director-Advisor, General’s said the UN Health Agency was hoping that coronavirus vaccinations could begin in some of the world’s poorest countries later this month or in February, calling on the global community to do more to ensure access to vaccines for all countries.
“We cannot do that on our own,” said Aylward, saying that WHO required the help of vaccine manufacturers to start vaccinating vulnerable populations in particular.
Aylward said the WHO was aiming to have “a rollout plan” outlining which developing countries might start receiving vaccines next month.
Still, the majority of the world’s Covid-19 vaccine supply has already been bought by rich countries.
The UN-backed initiative known as COVAX, which aims to distribute shots to developing countries, is short of vaccines, money and logistical assistance as donor countries scramble to protect their own people, especially in the wake of the newly identified Covid-19 variants in Britain and South Africa, which many officials blame for increased spread.
Intermixing, Not New Strains, Behind New Covid Spike
The WHO, however, said that the most recent peaks in transmission were due to “the increased mixing of people” rather than new versions.
WHO’s the 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. Van Kerkhove noted that during the summer, Covid-19 cases were down to single digits in most countries across Europe.
“We lost the battle because we changed our mixing patterns over the summer, into the fall and especially around Christmas and the new year,” she said, explaining that many people had multiple contacts with family and friends over the holidays.
“That has had a direct impact on the exponential growth that you have seen in many countries,” she said, describing the case count increase in some places as “vertical”.
Dr. Michael Ryan, WHO’s emergency chief, said while there are some evidence 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.