Pfizer vaccine found less effective against Delta

Israel's health ministry has released data indicating Pfizer's COVID-19 vaccine may have less efficacy than previously thought in preventing infection against the Delta variant.

According to data collected during the past month in Israel, it suggests that the Pfizer vaccine is 64 percent effective at preventing infection from the Delta variant. This compares to 94 percent efficacy against earlier strains of the virus.

Israeli health authorities said the Delta variant is now responsible for more than 90 percent of recent COVID-19 cases. World Health Organization data showed the country reporting 501 new cases on Monday, a 50 percent increase from the previous day, and 42 percent of those new cases occurred among vaccinated people.

The results were bleaker than those from another real-world study published in late May by Public Health England that showed the Pfizer jab was 88 percent effective at preventing infection from the Delta variant.

The Israeli study found that Pfizer efficacy at preventing hospitalization had dipped to 93 percent between early June and early July, from 98.2 percent the previous month.

A senior Israeli health ministry official said the data was concerning. According to a report by news outlet Ynet, the official said the vaccine is probably less effective for infections and mild illness and that the authorities may consider lengthening the testing period for returnees from abroad. They will also take the data into account when determining a potential booster vaccination program involving third shots.

Delta variant cases have surged in many nations in recent weeks, including the United Kingdom, where the strain is now responsible for 95 percent of all new cases. Based on figures from Public Health England, there were 50,824 confirmed new cases of the variant during the week ending July 2, bringing the total number of cases of the Delta strain detected in the UK to 161,981.

Studies suggest that the Delta variant is 60 percent more transmissible than Alpha, the UK's previous most dominant strain, which itself was more transmissible than the original strain of the novel coronavirus that triggered the pandemic.

'Far from over'

Despite the rising number of infections, the UK's Prime Minister Boris Johnson said the government is set to enter a new step of its road map for eased restrictions from July 19. This would allow all venues to reopen with no capacity caps, and put an end to social distancing, indoor mask mandates, and limits on the size of gatherings.

Johnson said that though the pandemic is far from over, the majority of those admitted to hospital with COVID-19 in the UK are unvaccinated. He said the UK's vaccination campaign has "greatly reduced mortality". A final decision on the transition to step 4 will be made on July 12.

In an announcement on Tuesday, British Health Secretary Sajid Javid said people who are fully vaccinated will not need to self-isolate if they are a close contact of a coronavirus case from Aug 16.

Javid told British lawmakers in Parliament that the same policy would also apply to anyone under the age of 18 from that date. He added the government would give more details later this week on self-isolation rules for international travelers.

Xinhua contributed to this story.