When Dr. Elad Maor tested negative for the coronavirus upon returning to Israel from abroad last month, he thought he was in the clear to get back to work and see friends and family. After all, he had received three doses of the Pfizer vaccine and had tested negative for the virus twice while in London, where he was attending a cardiology conference.

But on Nov. 27, after having close contact with 50 people, Maor tested positive for the coronavirus, The New York Times reported.

Maor’s test showed that the doctor was infected with the Omicron variant of the coronavirus, which was only detected in Israel for the first time earlier last week.

Yet in spite of the many close encounters Maor had with others during the time in which he was likely already infected and contagious, only one of those people — a 70-year-old with whom Maor shared an hour and a half long car ride — has so far tested positive for the virus, according to the Times. Most of Maor’s contacts were with people who had also received three vaccine doses.

While the number of those infected by Maor could still rise, with several test results from his contacts still being processed, the results are encouraging in the face of international concern that the Omicron variant might prove capable of evading the body’s vaccine-induced immune response.

Gili Regev-Yochay, director of infectious disease epidemiology at Sheba Medical Center in Ramat Gan, where Maor is an associate professor of cardiology, told the Times that while the case of Maor’s close contacts should not be considered proof that the virus is not more contagious than previous variants. But the small number of infections resulting from Maor’s interactions was encouraging, she added.

“But this does tell us that, in some cases, Omicron is not as infectious if you’re vaccinated. And I think that’s a major thing,” she told the Times.

Last week, Israel imposed a travel ban on foreigners for two weeks due to the variant and upgraded the quarantine and testing requirements for Israelis returning from abroad.