Authorities in Israel and Australia imposed new Covid-19 restrictions in response to the spread of the highly infectious Delta variant of the coronavirus, while India warned of a worrying new mutation, emphasizing how the morphing pathogen continues to challenge a return to pre-pandemic life world-wide.
The Delta variant is now in dozens of countries world-wide, and public-health officials in the U.S. say the variant, also known as B.1.617.2, is likely to become dominant in the country next month.
British scientists estimate that the Delta variant that was first identified in India spreads 40% to 80% faster than the Alpha variant, which fanned out from England to become the dominant version of the virus in the U.S. and much of the world. The Alpha variant is itself more infectious than the original virus first identified in China.
Dr. Tedros Adhanom Ghebreyesus,
director-general of the World Health Organization, said the worrisome variant is now present in 85 countries. “We are now starting to see increases in transmission around the world,” he said.
The WHO says the variant is spreading rapidly among unvaccinated populations, including in Africa, where it has been detected in 14 countries, including in most samples detected in Uganda and the Democratic Republic of Congo.
Indian officials say B.1.617.2 has itself mutated in a way that is causing concern. The versions of Delta that contain the new mutation, designated K417N, have been detected in at least 11 countries, including the U.S., U.K. and Japan, according to government health agency Public Health England.
Indian officials are calling the new versions Delta Plus, and scientists say there is no evidence that Delta Plus is significantly more transmissible or that anyone who catches it is more likely to die than with the Delta variant. But studies done on other variants containing the mutation indicate it might help the virus sidestep some of the body’s immune response. Lab research also indicates that the mutation might diminish the effectiveness of some monoclonal antibody treatments.
India has detected about 50 cases of Delta Plus so far through genomic sequencing.
“There is no reason to think at this point it’s worse than Delta, but there is no reason to think it’s an innocuous variant,” said Dr. Anurag Agrawal, director of the CSIR Institute of Genomics and Integrative Biology, which operates one of the labs charged with genomic sequencing of Covid-19 in India.
K417N “is not a major significant mutation by itself usually,” said Ravindra Gupta, professor of clinical microbiology at University of Cambridge. The mutation has also been found in versions of the Alpha variant, but failed to make that variant more dangerous, he said.
“We should keep an open mind and not start panicking,” he said.
The recent wave that overwhelmed India’s healthcare system in the spring has largely retreated, with new cases dropping to about 50,000 a day in recent days. Indian health officials have warned of another possible wave in the coming months. The country has reported more than 390,000 deaths and 30.1 million cases, according to the Health Ministry. India has fully vaccinated about 4% of its population of more than 1.3 billion.
In Australia, people who live or work in four areas in and near downtown Sydney and the iconic Bondi Beach have been ordered to stay home from Friday night for at least a week to stem the spread of the virus, which was first detected in the city last week. The last lockdown in Sydney, in December, was confined to the 70,000 residents of Sydney’s Northern Beaches area and lasted three weeks.
Israel is further reassessing its Covid-19 regulations after opening up its society and economy following several lockdowns last year. On Wednesday, the government delayed allowing foreign nationals to enter into the country for tourism from July 1 to Aug. 1.
The government this week expanded its vaccination campaign to include all 12- to 15-year-olds after a jump in infections among schoolchildren in a town in central Israel. The outbreak has since quickly spread geographically and to other groups of the population.
The outbreaks in Australia and Israel are small by global standards, and the countries offer a contrast in approach to the virus. Israel is one of the most highly vaccinated countries in the world—with about 80% of people over 16 having received two shots of the vaccine produced by
—while Australia has managed the pandemic by sealing its borders and imposing strict quarantine on the few people allowed in.
The spread of the Delta variant
In Israel, new cases of Covid-19 rose to over 200 on Thursday from around 10 a day for most of June.
On Friday, Australian officials said the outbreak included 65 cases, with 22 locally acquired cases having been recorded the day before. The country has recorded about 30,000 coronavirus cases, mostly among quarantined travelers from overseas, compared with more than 33 million cases in the U.S.
Preliminary findings by Israeli health officials suggest about 90% of new infections there were likely caused by the Delta variant, according to Ran Balicer, who leads an expert advisory panel on Covid-19 for the government. Children under 16, most of whom haven’t been vaccinated, accounted for about half of those infected, he said.
“The entrance of the Delta variant has changed the transmission dynamics,” said Prof. Balicer, who is also the chief innovation officer for Israel’s largest health-management organization, Clalit.
About half of adults infected in the outbreak of the Delta variant of Covid-19 in Israel were fully inoculated. These so-called breakthrough cases—defined as positive Covid-19 test results received at least two weeks after patients receive their final vaccine dose—are broadly expected as the Pfizer vaccine is highly effective but not 100% foolproof, according to Mr. Balicer.
Israeli health officials are optimistic that even if the variant does spread, evidence from countries such as the U.K. indicate the vaccine will prevent a large increase in severe illness and hospitalizations that plagued the country’s health system in previous outbreaks. Israel has recorded only five severe cases in the past 10 days, Prof. Balicer said, but whether more will emerge is too early to tell.
The rapid spread of Delta in the U.K., where it accounts for well over 90% of new infections, has already led to a one-month postponement of the planned ending of Covid-19 restrictions until July 19. In the past seven days, the number of people testing positive for the virus has increased by 50% compared with the previous week, to an average of almost 13,000 daily.
The increase has mainly been in younger, unvaccinated groups, and data show the variant is making very little headway among older, vaccinated adults. Over 60s account for just 4% of cases. Hospitalizations and deaths are rising as caseloads increase, but they remain well below the levels seen in previous stages of the pandemic, when vaccines weren’t available.
Analysis by England’s public-health agency suggests vaccines provide significant protection against Delta after two doses, reducing the risk of symptomatic illness by about 80% and the risk of hospitalization by around 96%. That is only slightly weaker than the protection vaccines confer against Alpha, also known as B.1.1.7.
The U.K. has recorded instances of breakthrough infections and even deaths among vaccinated individuals. Of 117 deaths linked to Delta in the U.K., 50 were among fully vaccinated adults. Scientists and public-health officials say the numbers are small and in line with what might be expected given the effectiveness of the vaccines. All those deaths were in people over 50, who would be expected to account for almost all deaths in the absence of vaccination.
The U.K. has one of the highest vaccination rates in the world, with 83% of adults with at least one dose and 61% with two.
—Jason Douglas in London contributed to this article.
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