Israel has defeated the Delta variant of the coronavirus and can expect six to eight months of COVID quiet, according to a leading virologist.
Dr. Rivka Abulafia-Lapid told The Times of Israel on Tuesday that the fourth wave is coming to an end, that Delta is highly unlikely to generate another wave, and that the strong spread of a new variant is improbable.
This is mostly due to the allocation of booster shots across age groups in Israel, which, given the functioning of the immune system, are likely to deliver longer-lasting protection than the initial two shots, she said.
“My estimate is that once we have three vaccines, protection will last for a year,” said Abulafia-Lapid, a senior doctor at Hadassah Medical Center and part of the Hebrew University’s faculty.
“There should be good memory in the body for around a year that can fight off COVID infection in many cases.”
She was slightly more conservative in predicting how long the boosters will protect the broader public — including those who have not had a booster shot — and said that she expects them to keep existing variants under control and prevent the wide spread of other variants for around six to eight months.
“We should expect new variants, but not now because populations are vaccinated well,” she said.
Abulafia-Lapid, who is an immunologist as well as a virologist, based her predictions on the performance of vaccines for other diseases. She said:
“With the initial shot you give the immune system a ‘first teaching,’ giving it the memory to fight a specific virus. With the second shot you ‘remind,’ and the third time the effect of the shot is even stronger.”
She gave the example of the human papillomavirus vaccine, which is given in Israel at birth, at two months and at six months; the hepatitis B vaccine, which is given at birth, one month and six months; and the rotavirus vaccine, which is given at two months, four months and 18 months. In each of these cases the third shot confers long-lasting protection, she said.
The drop in coronavirus cases in recent weeks is now allowing hospitals to breathe easier, as they witness a sharp decrease in serious cases. The number of new serious COVID cases per day in Israel has almost halved over the last two weeks — from just over 60 two weeks ago to 32 on Sunday.
Deaths have fallen from a seven-day average of 25 a month ago to 13 now, and the number of active cases, 25,127, is less than a third of what it was in mid-September.
Dr. Yael Paran, deputy head of epidemiology at Tel Aviv Sourasky Medical Center, shared Abulafia-Lapid’s optimism that the fourth wave is over and Delta vanquished.
“I think we’re seeing the end of the fourth surge, and it’s the result of three million taking a booster,” she said, adding: “This is a decrease that we believe will continue.”
She said that the effect of the boosters has been gradual, and is now convincing. “We saw the progression each time that boosters were offered to a new age group,” she said. “Two to three weeks later the number of infections dropped, and then the number of hospitalizations decreased.”
Ending a wave of infection and defeating a specific variant aren’t synonymous, and a specific variant can inflict two or more waves. But Paran thinks, like Abulafia-Lapid, the the fact Delta spread is slowing despite its highly contagious nature suggests that Israel has created an effective buffer against the variant.
She said that the timing of the decrease is a relief, as flu season is close and there has been concern about a possible twindemic effect, if a COVID wave and a spate of flu cases hit together.
Abulafia-Lapid said that she expects the fight against COVID to become an ongoing part of life and regular boosters, every six or twelve months, to become part of routine. “It’s going to be like flu and every year we’re going to have shots against specific strains that we anticipate ahead of time,” she said.
Source: Nathan Jeffay – TOI