Cancer experts are urging families to ensure their children get the HPV vaccine after it emerged that almost half of those eligible missed out last year because of the pandemic.

A study published in The Lancet on Thursday confirmed that the jab was cutting cases of cervical cancer by 87%. The results were hailed as powerful further evidence that the vaccine has prevented, and will continue to prevent, thousands of young people from falling ill.

The vaccine prevents infection from human papillomavirus, a group of viruses behind 90% of cervical cancer cases. It has been given to girls at the age of 12 and 13 in UK since 2008, and last year was made available to teenage boys for the first time. It also helps prevent cancers in men.

However, a government report seen by the Guardian shows that Covid-19 “had a significant impact on the uptake of the HPV vaccination programme” in the last academic year. Thousands of children missed out on getting the vaccine.

Schools were forced to close on 23 March 2020, which meant all school immunisation programmes were paused. Official figures show that only 54.4% of boys and 59.2% of girls in England got the HPV vaccine in 2019/20. That compared with a rate of 88.0% in girls in the previous academic year. Data for 2020/21 is due out in December, the UK Health Security Agency (UKHSA) said.

Samantha Dixon, chief executive of Jo’s Cervical Cancer Trust, welcomed The Lancet study but added: “We must not get complacent and must work to ensure every child has the opportunity to access their vaccination, especially as Covid continues to affect programme delivery.

“While uptake of the vaccine is relatively high, there are certain areas and communities where it is far lower. We’re living in a time of vaccine hesitancy and misinformation too so we must keep a really close eye on uptake to make sure confidence doesn’t fall.”

In the most extensive proof yet that the HPV jab is saving lives, the Lancet study found cervical cancer rates in women offered the vaccine between the ages of 12 and 13 (now in their 20s) were 87% lower than in an unvaccinated population.

“This research should provide compelling evidence of the success of the vaccine for teenagers and parents who are unsure about it,” said Dixon.

In England girls and boys aged 12 to 13 years should be offered a first dose when they are in school year eight. The 2nd dose is offered six to 24 months after the first. The NHS says it is important to have both doses of the vaccine for proper protection.

Schools are now trying to catch up after thousands of children missed out last year, but there have been reports that some who booked in for a catch-up HPV jab had appointments cancelled repeatedly.

Prof Peter Johnson, the NHS national clinical director for cancer, said it was vitally important that those eligible came forward for their HPV vaccine.

Vanessa Saliba, a consultant epidemiologist for UKHSA, said: “We encourage all who are eligible for the HPV vaccine to take it up when it is offered in school. All those eligible can catch up until their 25th birthday.”