Israel, the world’s third-most vaccinated country by share of the population, is experiencing a new outbreak of COVID-19 due to the more contagious Delta variant. The Health Ministry reported 343 new cases on July 4, the most cases in three months. Since first being detected on April 16, the Delta variant now comprises 90 percent of coronavirus cases in Israel.

The outbreak is particularly concerning given Israel’s vaccination program. According to Our World in Data, Israel has currently given at least one dose to 65 percent of its population, bested only by the United Kingdom’s 67 percent and Canada’s 69 percent. Until early June, Israel was the most vaccinated country by this metric. About 56 percent of Israelis are fully vaccinated, most with the vaccine produced by Pfizer.

The Health Ministry expects new cases to increase to 500-600 per day this week, while a team at Hebrew University warn that daily cases could reach 1,000 in two weeks. Daily new cases peaked at an all time high on January 17 with a seven-day-average just over of 8,600 per day and fell to a low of less than 10 on June 9.

With the resurgence of the virus, the government has reinstituted some measures, including an indoor mask mandate, and has resumed meetings of the so-called coronavirus cabinet.

Not only is the Delta variant more contagious, but it also appears to partially evade immunity provided by the vaccines which had previously been regarded as the most effective, including the Pfizer-BioNTech mRNA vaccine. According to the Ynet news site, Health Ministry data show that the Pfizer vaccine is now 64 percent effective in preventing infection, whereas before the rise of the Delta variant in Israel it was 94.3 percent effective.

This is corroborated by a study from Hadassah University Medical Center and Hebrew University, which estimate the Pfizer vaccine’s effectiveness against the Delta COVID-19 variant at 60-80 percent.

However, the vaccines do seem to largely protect against severe disease, hospitalization and death. Ynet reports that recent Health Ministry data show 93 percent effectiveness against severe disease, whereas previously it was 98.2 percent. Given the delay between infection and hospitalization, and between hospitalization and death, the real effectiveness against the Delta variant may be slightly lower.

This is comparable to initial data from the UK and Singapore on severe illness.

It is clear that, by not isolating vaccinated travelers returning from overseas and lifting social distancing and masking measures, the Israeli government missed an opportunity to curtail the Delta variant before it became entrenched in the country. Haaretz reports: “More than half of the new coronavirus patients are vaccinated (51 percent), according to the health ministry. Only 15 were returning travelers. One third of the new patients were children under 11, and another 13 percent were aged 12 to 18. In 50,000 tests carried out, 0.7 percent returned positive results.”

Outbreaks in Israel have been traced back to vaccinated individuals, including 75 high school students who got infected at a party after it spread from a vaccinated tourist to a vaccinated relative.

Despite the danger, particularly to teenagers and children, Prime Minister Naftali Bennett declared, “We do not want to impose any limits—not on parties, or on trips, or on anything,” and urged those 12 and older to get vaccinated.

More stringent measures are reportedly under discussion, but have not been implemented. The Times of Israel reports, “Former Health Ministry deputy director-general Itamar Grotto said the country should consider returning to the ‘Green Pass’ system that differentiates between vaccinated and non-vaccinated citizens regarding access to certain venues and activities.”

The “Green Pass” system ended on June 1, and had allowed vaccinated or those who recovered from a COVID-19 infection to eat indoors and attend certain events earlier than the population as a whole.

The Times of Israel also reported that the Israeli “Health Ministry is also considering mandating vaccinated parents of children who test positive for COVID[-19] to remain in quarantine until they receive a negative test … though the health minister expressed reservations about the economic toll of such a step.”

Meanwhile, the Delta variant continues to spread internationally and has become or is rapidly becoming dominant in a number of countries, including the United States. With practically every country less vaccinated than Israel (the US has 54 percent of its population at least partially vaccinated, for example, and only 24 percent of people worldwide are at least partially vaccinated), the dangers are immense for the majority of the population.

Moreover, these developments underscore a number of conclusions about the available vaccines and the way forward against the pandemic: First, the vaccines are remarkably effective, even against the worst variants thus far. It is a remarkable achievement of the human ability to scientifically understand the world that highly effective vaccines have been developed and distributed rapidly against a novel virus.

Second, the vaccines are not a “silver bullet” against the pandemic. The COVID-19 virus, through selective pressure, has and will continue to evolve to evade immunity as long as it is allowed to spread anywhere. While current evidence indicates it is unlikely that the Delta variant will produce a wave of infections in Israel as deadly as earlier ones, future variants may well evade immunity more comprehensively.

What is necessary—and has been necessary for some 18 months—is an internationally coordinated response to the pandemic. Vaccines are a critical component of this fight, and have to be distributed in an equitable fashion globally, rather than hoarded by the wealthiest countries. Additionally, the working class must fight against the premature lifting of public health measures such as social distancing and mask mandates, and for the expansion of health systems to adequately treat and isolate all those infected. The only political tendency fighting for such a program, based on the science of the pandemic and the social power of the working class, is the International Committee of the Fourth International and its affiliated Socialist Equality Parties around the world.