Herd immunity unlikely this year despite vaccine, U.N. says.
GENEVA — The World Health Organization’s chief scientist warned that even as countries start 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 crucial that countries and their populations maintain strict social distancing and other outbreak control measures for the foreseeable future. In recent weeks, Britain, the U.S., France, Canada, Germany, Israel, the Netherlands and others have begun vaccinating millions of their citizens against the coronavirus.
“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.
Scientists typically estimate that a vaccination rate of about 70 percent is needed for herd immunity, where entire populations are protected against a disease. But some fear that the extremely infectious nature of COVID-19 could require a significantly higher threshold.
Dr. Bruce Aylward, an adviser to WHO’s director-general, said the U.N. health agency was hoping vaccinations might begin later this month or in February in some of the world’s poorer countries, calling on the global community to do more to ensure access to vaccines.
“We cannot do that on our own,” Aylward said, saying WHO needed the cooperation of vaccine manufacturers to start immunizing vulnerable populations. Aylward said WHO was aiming to have “a rollout plan” detailing which developing countries might start receiving vaccines next month.
Still, the majority of the world’s COVID-19 vaccine supply has been bought by rich countries. The U.N.-backed initiative known as 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 in Britain and South Africa.
WHO, however, said that most of the recent spikes in transmission were due to “the increased mixing of people” rather than the new variants.
WHO’s technical lead on COVID-19, Maria Van Kerkhove, said that the spike incases innumerous 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.