The effectiveness of Pfizer's coronavirus vaccine in preventing infection has plummeted to 64% due to the spread of the Delta form in Israel, according to the Health Ministry, as officials consider the necessity for booster shots and new limitations.

The vaccine's effectiveness in avoiding symptomatic infection has dropped to 64% in the last month, according to the Health Ministry, which noted that the drop coincided with the rapid spread of the more contagious Delta from across Israel. The Pfizer shot, according to health officials, still provides good protection against serious sickness and hospitalization, with a 93 percent efficacy rate.

While the ministry did not include previous data in its statement, a report published in May stated that the Pfizer vaccine was 97 percent effective after two doses against serious disease. Private Israeli researchers discovered in March that the vaccine was 91.2 percent effective against any level of symptomatic infection.

The new information comes amid a minor uptick in the number of active cases in Israel, which reached 2,766 on Monday following 369 new infections, with the Delta strain accounting for more than 90% of the total. Around 70 patients were hospitalized as of July 4, half of them were in critical condition, compared to 21 patients in critical condition on June 19.

The rapid spread of the Delta strain, which was initially detected in India, has spurred Health Minister Nitzan Horowtiz to request two medical studies to determine whether a third vaccine shot is required, claiming that the results will provide “vital information” to policymakers. The tests will "evaluate the efficacy of the vaccine and the rate at which it wears off over time," according to Prime Minister Naftali Bennett's office.

While approximately 60% of Israel's 9.3 million residents have received at least one dosage of the Pfizer vaccine, helping to reduce daily infections from about 10,000 in January, instances continue to emerge among the inoculated. According to Ynet, more than half of the new infections reported last Friday were in people who had been vaccinated, highlighting the need for greater research.

In addition to the booster shots, health officials are considering reintroducing some pandemic restrictions, which were mostly dropped in March, as well as reintroducing a form of the coronavirus "passport" system, according to the Jerusalem Post. An inside mask requirement had previously been eliminated, but it was reinstated in late June as daily instances increased.

In the coming weeks, foreign passengers may be subjected to further testing and quarantine requirements, though the Health Ministry has yet to make a decision.