Snapchat, YouTube, TikTok and Reddit are involved in a new campaign encouraging more young people to get their coronavirus jab.
The social networks have teamed up with the government as it pushes ahead with the final stage of the vaccine rollout.
New data shows that one million vaccine appointments were booked in the two days after the NHS began offering COVID-19 jabs to all over-18s in England.
Although Health Secretary Matt Hancock has praised the "continued enthusiasm young people are showing for vaccines", data suggests Britons aged 16 to 29 have the highest levels of vaccine hesitancy.
According to the Office for National Statistics, 13% of people in this age group are unsure about getting a jab, despite the fact that the virus is spreading fastest among the nation's youngest.
It is hoped the collaboration with social networks will help prevent the spread of misinformation.
Snapchat users will be able to use new NHS stickers and a filter that says "I've had my vaccine".
Links will also be offered to reliable sources of information about how the jab works, and a series of Q&As with medical experts are going to be held on the prime minister's Snapchat account.
TikTok is also rolling out vaccine stickers and is working with a group of scientists who are using the video-sharing site to share clips about the jab.
Dr Karan Rangarajan, an NHS surgeon and influencer who has 3.9 million followers on TikTok, said: "Misinformation affects all groups equally and there is a large user base that is in their late teens or early 20s.
"They are also in the UK the last cohort to be eligible for the vaccine so it's a really important group to target."
He also warned that the most "dangerous and potent" combination of misinformation happened when falsehoods mixed some small level of truth.
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The new campaign comes on the day when the final stage of England's roadmap out of lockdown - which would have removed all remaining legal limits on social contact - was meant to take place.
This milestone has now been pushed back four weeks to 19 July after cases of the Delta variant, first detected in India, began to rise sharply.
The rush of vaccine appointments meant that an average of 21,000 bookings an hour - or six every second - were seen on Friday and Saturday.
Four in five adults have now received their first vaccination, NHS England figures suggest, with three in five adults now fully vaccinated.
NHS chief executive Sir Simon Stevens says "the finishing line is coming into sight" - and almost nine million people in their 20s and 30s have already had their first dose.