Delta variant ‘descendant’ hits Israel – is it time to panic?

It is said there are currently 56 “descendants” of the Delta variant, and they are all spreading at different rates and in competition with one another. 

A mall in Israel opens up after the country's third coronavirus lockdown. (photo credit: MARC ISRAEL SELLEM)
A mall in Israel opens up after the country's third coronavirus lockdown.
(photo credit: MARC ISRAEL SELLEM)

A new and potentially more transmittable version of the Delta variant has entered Israel just as the COVID infection rate has started to decline and the country prepares for flu season. Is the variant known as AY4.2 a reason to sound the alarms?

According to the Health Ministry, a single case of AY4.2 was identified in Israel in an 11-year-old boy who recently returned from a trip to Moldova. The boy tested positive for coronavirus while in isolation, the ministry said, and so far, it does not appear that others were infected.

However, with AY4.2 being as much as 10% to 15% more transmissible than its Delta grandparent, it is not unlikely that more cases are already in Israel and have just not yet been discovered, said Prof. Cyrille Cohen, head of the immunology lab at Bar-Ilan University.

There are currently 56 “descendants” of the Delta variant, he said, and they are all spreading at different rates and in competition with one another.

“AY4.2 is a descendant of AY4, a grandson of the Delta variant,” Cohen explained.

Israelis at Ben-Gurion Airport as coronavirus cases increase, August 5, 2021. (credit: AVSHALOM SASSONI/ MAARIV)Israelis at Ben-Gurion Airport as coronavirus cases increase, August 5, 2021. (credit: AVSHALOM SASSONI/ MAARIV)

As of an October 15 report by the UK Health Security Agency, the AY4.2 variant accounted for close to 10% of all sequenced cases in the country. But Cohen said the fact that it is 10% more transmissible needs to be put into perspective.

“This is not a catastrophe, compared to the other variants we have known,” he said.

The alpha variant was 50% more transmissible than the original Wuhan strain. The original Delta variant was 60% more transmissible than the Alpha.

Moreover, so far, the Pfizer vaccine has largely proven to be effective against stopping serious disease from all variants, said Dr. Nadav Sorek, assistant manager of the clinical microbiology laboratory at Assuta Medical Centers.

Nevertheless, infection levels in the United Kingdom are at an almost all-time high. The country is reporting more than 40,000 new coronavirus cases a day. In total, the UK has had 8.5 million infected people, more than three million of them having been diagnosed in the last several months.

The variant was enough to catch the attention of former Food and Drug Administration commissioner Dr. Scott Gottlieb, who tweeted about the situation over the weekend.

“UK reported its biggest one-day Covid case increase in 3 months just as the new delta variant AY.4  with the S:Y145H mutation in the spike reaches 8% of UK sequenced cases,” he wrote. “We need urgent research to figure out if this delta plus is more transmissible, has partial immune evasion?”

The variant has been in the UK since about July, he said, but it has been slowly increasing in prevalence.

“There’s no clear indication that it’s considerably more transmissible, but we should work to more quickly characterize these and other new variants. We have the tools,” he said. “This is not a cause for immediate concern but a reminder that we need robust systems to identify and characterize new variants. This needs to be a coordinated, global priority for COVID, the same as similar international efforts have become standard practice in influenza.”

The AY4.2 mutation is likely not the only explanation for the UK’s rising cases, said Cohen. In the summer, the country lifted all COVID restrictions, and a recent UK poll indicated that the public is unlikely to mask.

Moreover, the UK started administering the booster shot quite late compared to Israel – only in September – and so far, fewer than four million citizens have gotten their third shot. Also, only on September 20 did the UK started vaccinating adolescents.

Finally, the effectiveness of the vaccines given to the people who were jabbed first is likely waning, as Israeli and other research has shown.

The good news, of course, is that the rate of serious cases and the death toll has been going up much more slowly than the number of cases.

In general, the UK report said that “Delta remains the predominant variant, accounting for approximately 99.8% of sequenced cases in England as of 11 October 2021.

“AY.4.2 is noted to be expanding in England,” it said. “It is now a signal in monitoring, and assessment has commenced; there are also small numbers of new cases of Delta with E484K and Delta with E484Q.

“AY.4 remains dominant but other lineages introduced to the UK early have persisted over time,” the report said, and the country has four current variants of concern and 10 variants that are under investigation.

The development of variants is a natural process, Sorek and Cohen said.

“Think about an article you are writing, and in the article, there are 30,000 letters – more or less the number of letters in the genome of Sars-CoV-2,” Cohen explained. “You are copying and pasting that article by hand, so at some point, the more you copy it, the more likely you will make a mistake.”

These mistakes are mutations. When the mistake replicates and starts to spread, this becomes a new variant.

The variants compete with each other to survive. Those that develop advantages, such as being more transmittable, will become more robust, while the others will become extinct.

In the United States, the AY variants of the Delta variant are listed as variants of concern by the Centers for Disease Control and Prevention. However, the CDC’s vaccine tracker does not specifically mention AY4.2.

The Delta variant continues to make up more than 99% of all COVID-19 cases in the country.

In Israel, the Health Ministry is reporting between 1,000 and 2,000 new coronavirus cases a day, but it does not report which variants are tied to those cases. Cohen said that if one boy brought AY4.2 into Israel, it is likely that others have, too, but they may be asymptomatic or did not undergo genetic sequencing yet.

“There may also be other variants we are not aware of,” he said.

The Health and Tourism ministries are preparing to open up to vaccinated tourists beginning sometime next month, they have said. Cohen said he is supportive of the move, but that the country must remember “there is no free lunch.”

“To some extent, what is the difference if a tourist or an Israeli citizen is entering the country from abroad?” Cohen asked. “If both are vaccinated, it is just more of the same.”

He said he does not expect a major change in the probability per person to get new infections when the skies further reopen. However, he added that from the moment the number of people entering Israel is higher, “we multiply the chances of having new variants.

“We need to be aware of what is going on in Israel,” Cohen said, but when it comes to stopping the entry of new variants, short of shutting the airport again, “there is not much that we can do.”