WASHINGTON – Dr. Sharon Alroy-Preis, Israel's director of public health services, said Sunday that evidence points to the waning immunity in the COVID-19 vaccine, saying her two biggest concerns with the delta variant relate to its level of infectiousness and the rising rate of vaccinated individuals testing positive.
"It's 50 percent more infectious than the previous variant, which was 50 percent more infectious than the original one," Alroy-Preis told CBS' Face the Nation, noting that a third of Israel's population has not been covered, particularly Israel's large population of non-vaccinated children.
She added that 50 percent of the current infections are vaccinated individuals. "Previously we thought that fully vaccinated individuals are protected, but we now see that vaccine effectiveness is roughly 40 percent." She noted that while effectiveness remains high for severe disease, Israel is seeing diminished protection, particularly for those who have been vaccinated longer.
She said the debate between whether the infections are related to the timing of the vaccine versus whether the vaccine provides robust protection is "the million-dollar question," though evidence over the past several weeks shows there is, in fact, waning immunity.
"We compare people — both over the age of 60 but also between 16 and 59 — who were immunized early on and fully vaccinated by the end of January. We see infection rates among them that is 90 per 100,000, which is double of those who are fully vaccinated by March," she said, adding that "we see a drop in the vaccine effectiveness against disease for those who have been vaccinated early on, and we see it for both elderly people over the age of 60 but also for the younger."
She explained that Israel's decision to make available a booster shot is based on evidence of the difference between infection rates in those who were vaccinated early on and those vaccinated later, but also the evidence of increased hospitalizations of severe and critical cases among the 60 and above population who are fully immunized.
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"That, together with the fact that we're seeing lack of response to the vaccine over time, has led us to suggest and allow people to be vaccinated for a third time. It's not just that we're seeing more disease, but that they're getting into severe and critical conditions," she said.
Alroy-Preis said Israel was trying to reintroduce the "green pass" — meaning people could go into events with certificates that they have been vaccinated or recovered — or to be tested based on findings that the majority of vaccinated individuals are not spreading.
"We know that vaccinated individuals can infect others and we know they can be infected; they are 50 percent of confirmed cases on a daily basis. The question is whether they can infect others," she explained.
"We saw that 80 percent of vaccinated individuals who have become confirmed cases themselves had zero contact with confirmed cases, while 10 percent had one contact of confirmed cases," she said, adding that "their ability to infect others is 50 percent lower than those who are not vaccinated."
She noted while there is spread among household contacts, the risk of confirmed cases of vaccinated individuals infecting others is about 10 percent while the risk of infecting more than one individual is lower than 10 percent.