The Israeli Ministry of Health said to a local radio station the combination strain was detected by PCR tests, which are mandatory for all passengers arriving in Israel, at Ben Gurion Airport on Wednesday morning. The two patients were experiencing mild symptoms, including fever, headaches, and muscle aches, but were not ill enough to require specialized medical care, according to Israeli newspaper Haaretz.

The head of Israel’s COVID-19 program, Salman Zarka, speaking on Army Radio, did not mention where the patients were traveling from, but noted that they are a couple in their thirties who contracted the virus from their infant son. Israeli Health Ministry Director-General Nachman Ash, speaking to 103FM radio on Wednesday, said the variant could have come from within Israel. 

“It’s likely that they were infected before boarding the flight in Israel. The variant could have emerged here,” Ash said. “We don’t know what it means yet.”

Zarka noted that two COVID strains combining into a new variant was a common phenomenon, explaining that when there are two viruses in the same cell and it multiplies, “they exchange genetic material, creating a new virus.” 

Reassuring the public, Zarka added, “At this point, we’re not concerned about [the new variant leading to] serious cases.” 

Stealth Omicron

While the combination of Omicron and stealth Omicron has not put Israel on high alert, stealth Omicron alone has. 

Health Ministry officials have expressed concerns about the spread of BA.2. The Israeli government’s COVID Information Center warned in early March that BA.2 was accounting for an increasing share of COVID infections in Israel and “could slow the decline in infections and eventually perhaps even halt it.”

Stealth Omicron was first detected in Europe in late January, and has since become the leading strain behind new coronavirus infections in at least 18 countries.

Some scientists argue that stealth Omicron deserves its own Greek letter name in the coronavirus lexicon, but while BA.2 exhibits divergent mutations from the original Omicron variant, scientists have been more comfortable calling it a subvariant, as it shares many similar characteristics with its parent strain.

Stealth Omicron may have the ability to reinfect people after an initial case of Omicron, but vaccines appear to be effective against it. 

A study from Denmark found that prior infection with Omicron and vaccination seemed to be enough to provide abundant protection against the new strain.

There have also been recent reports of the BA.2 variant mutating with Delta, to create a new variant some researchers are calling Deltacron. That variant has also been recorded in Israel in the past week. According to national broadcaster Kan, Israel detected Deltacron among people returning from Europe, but there has been no community spread.