TEL AVIV, Israel — Pfizer Inc.’s COVID-19 vaccine was just 39% effective in keeping people from getting infected by the contagious delta variant in Israel in recent weeks, according to the country’s health ministry, but provided a strong shield against hospitalization and more severe forms of the virus.

The vaccine provided 88% protection against hospitalization and 91.4% against severe illness for an unspecified number of people studied between June 20 and July 17, according to a report Thursday from the health ministry.

The report said that the data could be skewed because of different ways of testing vaccinated groups of people versus those who hadn’t been inoculated.

The delta variant first emerged in India and is spreading around the globe as governments race to inoculate people, sometimes infecting those already fully vaccinated against COVID-19. The mutation has forced some countries to delay or rethink plans to loosen curbs on businesses, activity and travel.

Israel has had one of the world’s most effective inoculation drives, with 57% of the population fully vaccinated, but has seen a recent surge in infections due to delta. Critical cases have also climbed, but remain a fraction of the peak earlier this year.

Prime Minister Naftali Bennett has urged vaccine holdouts — who number 1.1 million people — to get inoculated, calling it the most effective way to defeat the delta strain. The government has also reinstated some restrictions for indoor events and plans to ban flights to several countries with rising infection rates, including the U.K. and Cyprus.