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Delta variant’s dominance in much of the world forces governments to change tack

The Delta variant of the coronavirus is now the dominant lineage in much of the world and has forced a rethink in public health strategy, including in countries like Israel, which a fortnight ago thought the battle against COIVD-19 won, writes MedicalBrief.

Then came the more infectious Delta variant, and a surge in cases. Initially, the Israeli authorities rejected the idea of booster vaccinations. But from Monday, Israel will begin offering a third dose of Pfizer/BioNTech's coronavirus vaccine as a booster shot for people with weakened immune systems, according to the Times of Israel.

This makes one of the first countries to offer booster shots to bolster protection against the rapidly spreading Delta variant. The Israeli Health Ministry is still determining whether an extra shot should be offered to the general public. Israel's Health Ministry announced last week that the effectiveness of the Pfizer vaccine had dropped to 64% against all COVID-19 infections, down from 95% in May.

Reuters reports that under what Israeli Prime Minister Naftali calls a policy of "soft suppression", the government wants Israelis to learn to live with the virus – involving the fewest possible restrictions and avoiding a fourth national lockdown that could do further harm to the economy, reports

“Implementing the strategy will entail taking certain risks but in the overall consideration, including economic factors, this is the necessary balance,” Bennett said last week.

The strategy has drawn comparisons with the UK government's plans to reopen England's economy from lockdown, though Israel is in the process of reinstating some curbs while London is lifting restrictions. The curbs that have been reinstated include the mandatory wearing of face masks indoors and quarantine for all people arriving in Israel.

"I am very much in favour of Israel's approach," said Nadav Davidovitch, director of the school of public health at Israel's Ben Gurion University, describing it as a "golden path" between Britain's easing of restrictions and countries such as Australia that take a tougher line.

New daily COVID-19 infections are running at about 450. The Delta variant, first identified in India, now makes up about 90% of cases.

Around 60% of Israel's 9.3 million population have received at least one shot of the Pfizer/BioNtech vaccine. On Sunday, the government began offering a third shot to people with a compromised immune system.

Some studies have shown that though high, the Pfizer/BioNTech vaccine's effectiveness against the Delta variant is lower than against other coronavirus strains.

Drawing criticism from some scientists, Pfizer and BioNTech have said they will ask U.S. and European regulators to authorise booster shots to head off increased risk of infection six months after inoculation. read more

Before the Delta variant arrived, Israel had estimated 75% of the population would need to be vaccinated to reach "herd immunity" – the level at which enough of a population are immunised to be able to effectively stop a disease spreading. The estimated threshold is now 80%.

An Asian contagion

In recent days, Indonesia has reported nearly twice as many coronavirus cases as the United States. Malaysia’s per capita caseload is roughly on par with those of Brazil and Iran. And the latest Covid surges in Japan and South Korea have prompted harsh new restrictions on movement there, reports the New York Times..

Across the Asia-Pacific region, the Delta variant is driving new outbreaks in places where transmission was once kept relatively low, but where the pace of vaccination has been too slow to contain the latest outbreaks. One result is that everyday activities are again being restricted, even as the West edges back to normalcy.

Indonesia, the world’s fourth most populous country, is a case in point. Its government once hoped that its archipelagic geography and youthful population would spare it a debilitating outbreak. But only about 13 percent of its 270 million people have received at least one dose of a Covid-19 vaccine, and the rise of Delta is pushing its health system to the brink and forcing some patients to hunt for oxygen.

On July 3, the government closed mosques, schools, shopping malls and sports facilities on two of Indonesia’s major islands for two weeks. But the daily average of new cases — more than 33,000 as of Sunday — has continued to climb. Officials said on Friday that they would extend the same emergency rules to other islands.

Intensive care wards in and around the capital, Jakarta, have been operating at full capacity, and doctors who received the vaccine made by the Chinese company Sinovac have been falling ill or dying. The government has said it will administer a third dose, of the Moderna vaccine, to about 1.5 million health workers starting this week.

Richer countries in the region have more resources to throw at the virus. But they, too, are vulnerable because they have made little progress in their vaccination drives. In Australia, Japan, New Zealand and South Korea, less than one person in three has had a shot, according to a New York Times tracker.

South Korea reported 1,378 new cases on Saturday, its third consecutive daily record. The government plans to raise restrictions to the highest level in Seoul, the capital, and some neighboring regions as of Monday. Schools will be closed, bars and nightclubs will be shut, and no more than two people will be allowed to meet in public after 6 p.m.

And in Japan, Tokyo’s fourth state of emergency will take effect on Monday, less than two weeks before the Summer Olympics begin there. Restaurants, department stores and other businesses will be asked to close early, and organizers of the Summer Games have said they will bar spectators from most events in Tokyo and its surrounding areas. A ceremony marking the Olympic torch’s arrival in the city late last week was held in a nearly empty park.

CNN produced a useful summary of the state-of-knowledge on the variants:

Delta

Also known as B.1.617.2, the Delta coronavirus variant is clearly more transmissible, but it is unclear if it causes more severe disease, As of July 3, it accounted for 51.7% of cases in the US, according to the US Centers for Disease Control and Prevention. By mid-June, the Delta variant accounted for 99% of Covid-19 cases in the UK, according to Public Health England, and it is set to account for 90% of cases in Europe by the end of August, according to the European Centre for Disease Prevention and Control. The World Health Organization (WHO) reports the Delta variant has been detected in 100 countries. It has overtaken the worrying Beta, or B.1.351 variant, in South Africa.

"Delta is the most transmissible of the variants identified so far," WHO Director-General Tedros Adhanom Ghebreyesus said last month.

"We know that the Delta variant has increased transmissibility and it is currently surging in pockets of the country with low vaccination rates," said CDC Director Dr Rochelle Walensky. "In parts of the Midwest and upper mountain states, CDCs early sequence data suggests the Delta variant accounts for approximately 80% of cases," she added.

What makes it so much more transmissible? It carries a cluster of mutations on the spike protein, the part of the virus used to attach to the cells it attacks, that appear to make it more effective at getting into cells, where it can replicate. Last Wednesday, a team of Chinese researchers reported people infected with Delta carried viral loads – the amount of virus in their bodies – that were 1,200 times higher than people infected with older lineages. It also appears to reach a point where it can be transmitted two days earlier, on average, after infection, the researchers said.

However, multiple studies indicate all three vaccines authorised for use in the US can protect people against Delta. They all show the vaccines generate a cushion of protection that more than makes up for the variant's ability to compete with the immune response. They don't prevent all infections, but greatly reduce the likelihood of severe disease, hospitalisation and death.

Delta does evade the immune system, which may mean people who have been infected once with an older variant may be more likely to catch it again. It also eludes the effects of a monoclonal antibody treatment called bamlanivimab, made by Eli Lilly and Co, but is vulnerable to the protection offered by other monoclonal antibody treatments.

A French study showed the Delta variant was four times less sensitive than the Alpha variant to blood collected from people who had recovered from COVID-19 up to 12 months ago. The same researchers found a single dose of either the Pfizer/BioNTech or AstraZeneca COVID-19 vaccines was not effective against either the Beta or Delta variants. Antibodies in blood from just 10% of people in the study neutralised the Delta variant after a single vaccine dose. But a second dose of vaccine elicited an immune response in 95% of people in the study, though antibodies were significantly less potent against the Delta variant compared with the Beta variant.

"Early data from Scotland, from individuals who tested positive from 1 April to 21 June 2021, showed an increased risk of hospitalisation among cases infected with the Delta variant compared with those infected with the Alpha variant," WHO noted.

Delta carries a distinct cluster of mutations compared with other variants, including one called L452R known to increase transmissibility. It does not carry two other worrying mutations known as E484K and N501Y, which are seen in the B.1.1.7 or Alpha variant first seen in Britain, and which swept many countries at the end of 2020 and the beginning of 2021, and also in the B.1.351 variant of Beta variant first seen in South Africa, as well as the P.1 or Gamma variant.

Alpha
This past spring, it was the B.1.1.7 or Alpha variant of coronavirus that was worrying public health officials. It swept across England quickly and then out into the world, quickly becoming the dominant lineage in the US. As of this past Sunday, it accounted for just 28.7% of cases in the US, the CDC estimates, as it was replaced by Delta. It was shown to be at least 50% more transmissible than older lineages. It carries 23 mutations, including one called N501Y that increases transmission. It's fully susceptible to monoclonal antibody treatments and vaccines.

Beta
First seen in South Africa, the B.1.351 or Beta variant has both the E484K mutation that is linked with immune escape and the N501Y mutation suspected of helping make many other variants more contagious. It has been shown to be 50% more transmissible than older strains and evades Lilly's dual monoclonal antibody treatment but not others. Blood tests and real-life use both suggest it can infect people who have recovered from coronavirus and also people who have been vaccinated against COVID-19. Vaccine makers trying to get out ahead of the new variants by developing booster shots have focused on B.1.351, as it's the variant scientists most fear could elude vaccine protection. But partial escape doesn't mean full escape, and vaccines are still expected to protect people to some degree. It's being overtaken by Delta in South Africa and has never gained much of a foothold in the US, where it currently accounts for 0.2% of new cases, according to CDC.

Gamma
The P.1 or Gamma variant that swept Brazil currently accounts for 8.9% of new infections in the US, according to CDC. Gamma carries both the E484K and N501Y mutations, with more than 30 others. It has been demonstrated to evade the effects of Lilly's monoclonal antibody treatment but not one made by Regeneron. Blood tests show it might partly escape both natural and vaccine-elicited immune responses.

Epsilon
The B.1.427 and B.1.429 variants are usually lumped together and known as Epsilon. First seen in California, this one has the same L452R mutation carried by Delta, but not some of its other mutations and has not taken off in the way Delta has. "Epsilon (B.1.427/B.1.429) has been associated with increased transmissibility, a modest decrease in susceptibility to some antibody treatments, and reduced neutralisation by convalescent and post-vaccination sera," WHO says.

Iota
First seen in New York last November, the B.1.526 or Iota variant accounts for 3% of US cases, CDC estimates. That's down from 9% of samples last April. It has what's called a 484 mutation that should help the virus attach more easily to the cells it infects and also makes the virus less recogniseable to the immune system.

Eta
First seen in the UK and Nigeria, Eta, also known as B.1.525, carries the E484K mutation. It's decreasing in frequency in the US, now accounting for almost no samples tested.

Zeta
Circulating in Brazil since last year, this variant, also known as P.2, also carries the worrying E484K mutation and has not been found widely globally. It's almost disappeared in the US, according to the CDC.

Hereʼs what you need to know about the Lambda COVID variant

A CNBC Health & Science report says that more than 18 months into the COVID-19 pandemic, the world is used to news of new variants of the virus by now, particularly those that have, one by one, supplanted previous versions of the disease.

Some mutations of the virus, like the Alpha variant and the Delta variant, discovered first in the UK and India, respectively, have been more transmissible than previous iterations of the virus and have gone on to dominate globally. Whenever a new variant of the coronavirus emerges, scientists watch it closely.

While the world is still contending with the rapid spread of the Delta variant, which has usurped the Alpha strain in terms of transmissibility and the potential to cause hospitalisations in unvaccinated people, there is now a new variant that experts are monitoring: the Lambda variant.

Hereʼs what we know (and donʼt know) about it. What is the Lambda variant?

The Lambda variant, or “C.37” as the lineage has been designated, has been spreading rapidly in South America, particularly in Peru where the earliest documented samples of the virus date from August 2020. However, it was only flagged up as a “variant of interest” by the World Health Organization on June 14 this year .as cases attributed to the variant had spread noticeably.

In its report in mid-June, the WHO reported that “Lambda has been associated with substantive rates of community transmission in multiple countries, with rising prevalence over time concurrent with increased COVID-19 incidence” and that more investigations would be carried out into the variant.

Where is it exactly?
The WHO noted in its 15 June report that the Lambda variant had been detected in 29 countries, territories or areas in five WHO regions, although it has a stronger presence in South America.

“Authorities in Peru reported that 81% of Covid-19 cases sequenced since April 2021 were associated with Lambda. Argentina reported increasing prevalence of Lambda since the third week of February 2021, and between 2 April and 19 May 2021, the variant accounted for 37% of the Covid-19 cases sequenced,” the WHO noted.

Meanwhile, in Chile, the prevalence of Lambda has increased over time, accounting for 32% of sequenced cases reported in the past 60 days, the WHO said, adding that it was co-circulating at similar rates to the Gamma variant but was “out-competing” the Alpha variant in the same time period.

By 24 June, the Lambda variant had been detected in cases in 26 countries, according to Public Health England data. This included Chile, Argentina, Peru, Ecuador, Brazil and Colombia as well as the US, Canada, Germany, Spain, Israel, France, the UK and Zimbabwe, among others.

Is it more dangerous?
The WHO and other public health bodies are trying to understand how it compares with other strains of the virus, including whether it could be more transmissible and more resistant to vaccines. In mid-June, the WHO said “Lambda carries a number of mutations with suspected phenotypic implications, such as a potential increased transmissibility or possible increased resistance to neutralising antibodies”.

Noting the specific mutations in the spike protein (some of which have been described as unusual by experts) the WHO said that: “There is currently limited evidence on the full extent of the impact associated with these genomic changes” and further studies are needed “to better understand the impact on countermeasures [against COVID-19] and to control the spread”.

Itʼs important to note that the Lambda variant is still one step below being designated a “variant of concern” like the Alpha or Delta mutations. In a news conference last week, the WHOʼs technical lead on COVID-19, Maria Van Kerkhove, was asked what would need to happen for it to change its definition of the Lambda variant.

“It would become a variant of concern if it has demonstrated pathways of increased transmissibility, if it has increased severity for example or if it has some kind of impact on our countermeasures,” she said.

Do vaccines work against it?
Again, more studies are needed about the effect that the Lambda variant has on vaccine efficacy, particularly on vaccines widely available in the West, such as those from Pfizer-BioNTech, Moderna or Oxford- AstraZeneca. But questions have been raised in parts of South America over the effectiveness of Chinese vaccines, which have been those deployed predominantly in the region, as cases linked to the lambda variant spread and infection rates rise alongside vaccination programmes. Brazil, Chile and Peru all rely heavily on Chinese COVID vaccines Sinovac or Sinopharm, but vaccination rates differ wildly across South America.

One study carried out by the University of Chile in Santiago, which looked at healthcare workers who had received two doses of Chinaʼs CoronaVac (or Sinovac) vaccine suggested that the mutations present in the spike protein of the Lambda variant “confer increased infectivity and immune escape from neutralising antibodies”. The study, published on July 1, has not yet been peer-reviewed.

Chinese vaccines face rising doubts about their efficacy, compounded by a lack of data on their protection against the more transmissible Delta variant. Weekly COVID cases, adjusted for population, have remained elevated in at least six of the worldʼs most inoculated countries — and five of those nations rely on vaccines from China. No vaccine currently available is seen as 100% effective at preventing COVID-19 infection, although Chinaʼs vaccines have so far fared worse in clinical trials. Sinovac was seen as 50.4% effective in a Brazilian trial whose results were published in January. A study in the UAE published last December found the Sinopharm vaccine to be 86% effective.

China has defended its vaccines, however, and experts note that countries shouldnʼt stop using Chinese COVID vaccines, especially amid a lack of supply in low- and middle-income nations.

Living with COVID-19: Israel changes strategy as Delta variant hits

Short on vaccines, Asia grapples with Delta-driven outbreaks

Full CNN report – Coronavirus variant

COVID variants: here's what we know (Open access)

Full CNBC Health & Science report – Hereʼs what you need to know about the lambda Covid variant (Open access)

See more from MedicalBrief archives:
Delta variant may be transmitted in ‘scarily fleeting’ contacts

Previous COVID infection may not offer long-term protection – UK study

https://www.medicalbrief.co.za/archives/previous-covid-infection-may-not-offer-long-term-protection-uk-study/

UK variant 45% more infectious than wild-type strain of SARS-CoV-2

https://www.medicalbrief.co.za/archives/uk-variant-45-more-infectious-than-wild-type-strain-of-sars-cov-2/

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