Delta Sub-Variant AY.4.2 Continues to Spread As Child Israel's First Case

Israel has reported a case of the new Delta AY.4.2 COVID variant, according to the country's health ministry.

The variant was detected in an 11-year-old boy who had flown into Israel's Ben Gurion International Airport, the ministry said on Tuesday. He was ordered to go into isolation.

An investigation is underway and the ministry added that there were no additional confirmed contacts as of October 20.

According to The Jerusalem Post, the boy had returned to Israel from Moldova and the AY.4.2 case is the first to be reported in Israel.

AY.4.2 is a COVID variant that has stemmed from its parent lineage AY.4, which itself is a variant of Delta.

AY.4.2 is characterized by two mutations in its spike protein: Y145H and A222V.

It should be noted that no cases of AY.4.2 have been reported in Israel over the past week according to the variant-tracking database GISAID. However, this may be due to a delay in reporting.

AY.4.2 has come to the attention of researchers due to the variant rising rapidly in the U.K. since July this year.

According to Outbreak.Info, which collects GISAID data in order to show how variants spread geographically, AY.4.2 is almost completely restricted to the U.K. at the moment.

It states that AY.4.2, defined as AY.4 with the mutations Y145H and A222V, has been found in 14,970 COVID virus sequences worldwide overall. Of those, 14,247 have been in the U.K.

Still, the virus is being assessed because it is currently accounting for between 7 and 8 percent of new U.K. COVID sequences. This means the variant appears to be increasing its share of cases compared to Delta.

At the moment, it's unclear whether AY.4.2 warrants concern or whether it might have a significant advantage over Delta.

Professor Francois Balloux, director of the Genetics Institute at University College London, has suggested AY.4.2 may be 10 percent more transmissible than its parent lineage based on its recent U.K. rise.

To summarise, the recent rise in the UK of AY.4.2 would be compatible with a transmissibility advantage of ~10%. As such, it feels worthwhile keeping an eye on it. Though, based on its genetic make-up, it is not a priori an obvious VoC candidate.

— Prof Francois Balloux (@BallouxFrancois) October 16, 2021

However, he later tweeted that this would not explain much of the recent case rises in the U.K.

AY.4.2 does not appear to have established a foothold in the U.S., where only three cases of AY.4 with Y145H and A222V have been reported. The cases occurred in North Carolina, California, and the District of Columbia, according to Outbreak.Info.

A lab worker holds a suspected COVID sample at the Maccabi Health Services laboratory in Israel in May 2020. The country has recorded a case of the COVID AY.4.2 variant. Gil Cohen-Magen/AFP / Getty