There's a big programme taking place to give girls the chance to have an injection to help stop them getting a type of cancer called cervical cancer when they're older.
Sadly one 14-year-old died after having the vaccine. Investigations are being carried out to find out what happened.
It's possible she had health problems and her death was nothing to do with the vaccine.
But lots of you are worried about it and we've asked children's health expert Dr David Elliman to answer some questions.
All we know at this stage is that a 14-year-old girl tragically died the same day as she was given the vaccine. We don't know her past medical history or what actually caused her death.
Is her death linked to the vaccine?
It's impossible to say until investigations have taken place. It may have been a coincidence. Sadly, some young people do die suddenly for a variety of reasons and sometimes they have been healthy until their death.
Is the vaccine safe?
Experts say it is safe. Lots of safety studies took place before the introduction of the vaccine, but they may not have picked up very rare events. But since the vaccine was introduced it has been monitored very carefully. Millions of doses are being given but we are not aware of any similar tragedies.
Very rarely a person can have a life-threatening allergic reaction after a vaccine, medicine or food. It's very rare for them to die after having a vaccine.
Could there be a problem with a particular batch of vaccine?
Until we know more, it's impossible to say. But, just in case, the batch from which this young girl was immunised has been quarantined and won't be used until investigations are complete.
It's worth remembering that no other major problems have been reported with this batch.
What if I have already had a dose from this batch?
Even in the unlikely event that the tragic death was related to the vaccine, you can be reassured that any similar reaction would be obvious by now. You have no need to worry.
Should we go on using the vaccine?
It's safe for other batches of the vaccine to be used. The safety record of this vaccine is good, so it is very unlikely that there is any problem with the vaccine in general.
At the moment the vaccination programme will continue unchanged, with the exception that the batch in question will not be used.