The nurse received a first dose of the Pfizer/BioNtech in December last year
Three weeks later she began suffering Covid-19 symptoms and tested positive
Experts have warned that it takes time for immunity to Covid-19 to build up
The Pfizer vaccine offers up to 95 percent protection against Covid-19
A nurse in Wales caught coronavirus three weeks after getting the vaccine, prompting experts to warn that it takes time for immunity to the virus to build up.
The nurse, who has been working for the Hywel Dda University Health Board area, said that she contracted Covid-19 while waiting for the second dose of the Pfizer-BioNtech developed vaccine.
While the vaccine 'reduces your chance of suffering,' the health board said, 'no vaccine is 100 percent effective.'
Experts have warned that vaccines can take weeks to build immunity, and that people must still be careful to follow coronavirus rules after having the jab.
Speaking to the BBC, the nurse - who chose not to be identified - said she was 'angry and heartbroken' to have caught Covid at this stage.
She said that she was initially relieved to be offered the chance to be given the vaccine, and while she struggled to get an appointment, she was given her first dose of the Pzizer-BioNtech vaccine in December last year.
'It gave me peace of mind. It made me feel safer and that I was doing the right thing for my family... but it gives a false sense of security,' she told the broadcaster.
The nurse said that it was explained to her that it would take 10 days for the vaccine to offer some protection against Covic-19, and reduce the risk of transmission.
But three weeks after being given the jab, she said she began to feel unwell, suffering from 'quite severe symptoms' of a bad cough, high temperature and breathlessness, and was 'shocked' when she tested positive for the coronavirus - followed by her partner and one of her children.
Vaccinations have been shown to prevent severe infection, so even if people do become infected, they would be protected from becoming seriously unwell.
So far, three vaccines have been approved for use in the UK, with the Pfizer-BioNtech vaccine - which started to be rolled out to the country's most vulnerable people last month - offering up to 95 percent protection against Covid-19.
The Pfizer vaccine and another developed by Oxford University and AstraZeneca are now being rolled out. A third from Moderna was approved for use in the UK Friday.
Professor Tim Spector, who heads up the ZOE Symptom Tracker App study, told The Sun that junior NHS staff members have also reported getting the virus after being given the Pfizer jab.
'We are getting reports of reinfections, some soon after vaccination, "I'm a junior doctor and have had Covid twice the last one five days post vaccination..."', he wrote on Twitter.
'Remember vaccinations take several weeks to have a preventive effect so keep alert and keep logging!'
Wales' First Minister Mark Drakeford advised people receiving the vaccine to 'continue to act in a precautionary way' after being administered the jab.
He said those people should 'recognise the new protection that they have' but 'recognise as well that for many weeks, and for some months ahead, coronavirus is going to continue to be a feature of all our lives'.
Deputy Chief Executive Dr Philip Kloer of the Hywel Dda health board released a statement saying it was 'always distressing' to hear about staff catching Covid-19.
'Whilst the vaccine reduces your chance of suffering from Covid-19, no vaccine is 100 per cent effective,' he said.
'There is particular risk that you may have contracted Covid-19 immediately prior to having the vaccine without knowing it, or that you may contract it in the week or two following vaccination as your body builds up protection.
'We have communicated the UK policy and assurances on second doses to our staff and assured them they will receive their second dose within 12 weeks of the first.'
He added: 'Working within the NHS at the moment is very challenging and we acknowledge how difficult this is.
'Staff have worked tirelessly and made many sacrifices on behalf of caring for our communities and we are extremely grateful. We have put in place additional support and counselling and psychological support services.'
The board said that so far it has already vaccinated more than 10,000 high-risk people, including front line NHS staff.
Prof Spector also noted that you can't test positive for the coronavirus as a result of getting the vaccine, because while the jabs contain active mRNA, they do not contain an active virus.
The body is given a set of instructions through the use of mRNA in the jabs, which tell cells to make proteins and send them to different parts of the body.
Rollout of the Pfizer vaccine began last year on December 8, targeting the country's most vulnerable people, such as residents in a care home for older adults and staff working in care homes for older adults, as well as those over the age of 80 and other front line health a social care workers.
Originally, advice in the UK was that after having the first dose of the vaccine, people would need the second dose three weeks later.
But this later changed to 12 weeks on advice of the UK's chief medical officers.
The World Health Organisation (WHO) however, does not recommend the UK's approach, but has 'made a provision for countries in exceptional circumstances of vaccine supply constraints and epidemiological settings' to delay the second dose for a few weeks to enable more people to get the first dose.
Pfizer said that it had tested the vaccine's effectiveness only when the two doses were given up to 21 days apart from one-another.
Britain today suffered its deadliest day since the Covid pandemic began after health chiefs declared 1,325 more Covid fatalities and another record-high 68,053 infections.
The grisly death toll - which has doubled in a week and surpasses the 1,224 declared on April 21 in the darkest day of the first wave - takes the UK to the brink of almost 80,000 victims. Experts fear the daily death counts will continue to spiral because of rocketing cases and hospitalisations, piling further pressure on Boris Johnson to speed up the sluggish vaccination programme designed to get Britain out of lockdown by mid-February.
Department of Health figures show the UK has recorded more than 50,000 cases for 11 days in a row, with the five worst days of the pandemic all occurring since the start of 2021. Cases have risen by almost 30 per cent week-on-week.
But a senior SAGE official today warned the actual number of Britons currently getting infected every day is closer to 150,000, claiming that the size of the second wave is now way worse than the first.
The source also fears England's third national lockdown will not slam the R rate down as it did in March because the country was dealing with a more infectious mutated strain and because adherence to the rules has dwindled.
Draconian measures announced two days ago have yet to have an effect on the crisis because it can take a week for patients to develop symptoms and get tested. But the SAGE official argued that the tough restrictions will curb the spread of the virus because they curb social interaction, which the virus thrives on.
In yet another sign that darker days lie ahead, No10s advisory panel today revealed the R rate could be as high as 1.4 in the UK or at the crucial mark of one, with outbreaks growing at similar speeds across all seven regions of England.
But the figure reflects the situation Britain found itself in before Christmas and not the current picture because of the data used to calculate it. SAGE last week estimated the figure the average number of people each infected person passes the virus onto was between 1.1 and 1.3.
Britain today approved Moderna's coronavirus vaccine - but won't be able to get any of the 17million doses it has bought until March at the earliest.
Moderna's Covid jab is the third to be given the green light by regulators in the UK, joining the vaccines made by Pfizer/BioNTech and Oxford University/AstraZeneca.
Health Secretary Matt Hancock admitted that No10 won't get any doses until the spring but said: 'This is further great news and another weapon in our arsenal to tame this awful disease.' And Business Secretary Alok Sharma described it as 'another huge step towards ending lockdown'.
The EU - which approved the same vaccine two days ago - will get supplies of the jab from next week after health chiefs struck a deal with the US-firm to buy 180million doses last summer.
With Britain now scrambling to vaccinate 13million vulnerable Britons in the hope of ending the constant cycle of lockdowns by mid-February, an extra jab could have been a blessing.
Moderna's vaccine was the second one to announce the results of its last-stage clinical trials when it did so in November, after Pfizer and BioNTech. They showed the vaccine appeared to prevent 94.5 per cent of Covid cases.
Moderna's and Pfizer's use the same technology, which had never been tried before, so scientists said it would have been a big gamble for the UK to order both.