Health officials on Tuesday evening reported the first identified case of the highly contagious Delta sub-variant AY.4.2 in Israel.
Follow Israel Hayom on Facebook and Twitter
The variant has recently been detected in several European countries.
The infected person is an 11-year-old boy who tested positive on his return from Moldova.
Although they have yet to express serious concern, officials are investigating whether the new strain is more contagious than the delta variant.
In an interview with Kan Radio, Health Ministry Director-General Nachman Ash said the sub-variant was "probably more infectious than Delta, but not significantly so."
He said, "There will always be variants. We need to follow [them] and if necessary, take special steps."
As for the recent decline in the vaccination rate, Ash warned an insufficient rate could result in a potential fifth wave.
Earlier, a spokesperson for British Prime Minister Boris Johnson said there was no evidence AY.4.2 spreads more easily.
The news comes as Israel appears to be exiting the fourth wave of the coronavirus, with improving daily numbers coming out of the Health Ministry.
According to recent ministry data, the country's infection rate stands at 1.42%. Of the 110,843 people who tested for the virus Tuesday, 1,487 were found to have COVID-19.
There are 17,126 active cases of the virus. There are 353 people in serious condition, 157 of whom are on ventilators. Although 1,293,699 Israelis have recovered from the virus since the start of the break, 8,021 have died.
According to the Health Ministry, 3,865,633 Israelis have received all three eligible doses of the coronavirus vaccine. While 5,704,991 have received at least two doses, and 3,865,633 have received at least one jab.
A first-of-its-kind study from Sourasky Medical Center in Tel Aviv showed a 50-fold increase in coronavirus antibody levels following vaccination with the third, recently approved third dose. The study compared antibody levels among 346 hospital workers aged 60 and over before and after receiving the booster shot.
The study, which appeared in the Lancet Microbe medical journal, is one of the first studies of the third dose's impact on antibody levels to be published in a medical journal.
Subscribe to Israel Hayom's daily newsletter and never miss our top stories!
Eight months after receiving the second dose of the vaccine, the median level of antibodies among the study's participants was 3.67. It should be noted that when that level drops below 1, an individual is considered not to have any antibodies. However, 10 days after receiving the booster shot, that level had increased to over 150 for 95.7% of participants.
The researchers intend to carry out another small study on a group of 10 people who developed low levels of antibodies and two who did not develop antibodies at all.
The average participant in the study was aged 67. Of the 346 participants, 215 were women.
"The study demonstrates and proves the booster shot's great efficiency at restoring antibody levels in the blood of the vaccinated after it significantly decreased a few months after receiving the second dose," Dr. Esther Saiag, deputy director of Medical Systems Operations and Information and Computer Systems at Sourasky Medical Center, who carried out the study with Dr. David Bomza, said.
"The study's findings are in line with the waning of the fourth wave in Israel, along with the impressive levels of inoculation with the third dose among the general public. Alongside what we are now seeing happening in the country, the research shows what goes on 'behind the scenes' with the booster, meaning the increase in antibody levels."
According to Dr. Saiag, "The study's participants were healthy people and not immune-compromised, and still there were two whose antibody levels remained very low after receiving the booster shot. I intend to ask for clinical information and try to find a common denominator or explanation for these two vaccinated individuals, as well as for another around 10 who did not develop a maximal response."
She added: "We still see there are a few people who get infected after receiving the third vaccine dose. It may be that these people are taking certain medications or they suffer from autoimmune disorders."
While Saiag said that while the research could not predict how long antibody levels would remain high and if a fourth dose would be necessary. She said they were following up with participants to that end.
Data provided by Pfizer ahead of Israel's booster campaign showed a five- to 19-fold increase in antibody levels following inoculation with the third dose.
i24NEWS contributed to this report.
