Facebook posts wrongly link nasal flu vaccines to increase in strep A infections

Full Fact has identified dozens of false claims linking recent deaths in children from strep A infections in the UK to the nasal flu vaccine have been shared thousands of times on Facebook in recent days.

The nasal flu vaccine doesn’t contain strep A, and there is no evidence at all that the vaccination of school children against flu has anything to do with the increase in cases. 

One post shared over 300 times says: “Four weeks ago, all UK PRIMARY aged children get live flu nasal spray. Today, primary aged children dying from strep [...] Dot to dot.” 

Another social media user wrote, in a post shared more than 1,100 times: “Four weeks ago, UK school children received a "floo"nasal spray. Today, there are children are dying [sic] from Strep-A.”

Another post, which has been copied, screenshotted and shared hundreds of times, explicitly claims that strep A infections are a side effect of the nasal flu spray. 

Strep A, or group A streptococcus, is a type of bacteria sometimes found in the throat or on the skin. It usually causes mild illnesses such as a sore throat, though many people can carry the bacteria harmlessly without developing illness. In some cases it can cause scarlet fever, which is usually mild.

The symptoms of scarlet fever include a sore throat, headache, and fever, along with a fine, pinkish or red body rash with a sandpapery feel. On darker skin, the rash can be more difficult to detect visually but will also have a sandpapery feel. 

The bacteria can also cause more serious and even life-threatening infections called invasive group A strep (iGAS) infections when the bacteria enters deeper into the body, sometimes including the bloodstream. 

The UK Health Security Agency (UKHSA) has said that there has been an increased rate of scarlet fever and invasive group A strep recently. 

As of 2 December, sadly five deaths of children were recorded within 7 days of an iGAS diagnosis in children under 10 in England. Dr Colin Brown, deputy director of the UKHSA has said: “Make sure you talk to a health professional if your child is showing signs of deteriorating after a bout of scarlet fever, a sore throat, or a respiratory infection.”

The UKHSA advises parents to call 111 or see their GP if: 

• your child is getting worse 
• your child is feeding or eating less than normal
• your child has had a dry nappy for more than 12 hours or is showing other signs of dehydration
• your child has a high temperature (above 38°C in infants under three months, and 39°C in older children)
• your baby is hotter than usual when you touch their back or chest or feels sweaty
• or if your child is very tired or irritable. 

If your child is having difficulty breathing, if there are pauses when your child breathes, if their skin, tongue or lips are blue or if they are floppy and will not wake up or stay awake, the UKHSA says parents should call 999 or go to A&E. 

Nasal flu vaccine doesn’t contain strep A

Professor Andrew Pollard, director of the Oxford Vaccine Group, told Full Fact: “Influenza vaccines do not contain group A streptococcus, they contain weakened strains of flu. 

“They are very carefully regulated by the Medicines and Healthcare products Regulatory Agency and are tested to show that there is no contamination with bacteria before they are released. 

“Group A streptococcal bacteria are very common in children and spread from person-to-person, often without symptoms, but can commonly cause sore throats and very rarely severe disease as in the recent cases.” 

Former chair of the BMA’s Public Health Medicine Committee Dr Peter English, a retired consultant specialising in communicable disease control, said there was “absolutely no plausibility to this claim”. 

He added: “Flu infection increases the risk of subsequent bacterial infections. If anything, getting protected against flu is likely to decrease the risk of streptococcal infections.”

Dr Simon Clarke, associate professor in cellular microbiology at the University of Reading told Full Fact: “The claims that it [the nasal flu vaccine] has group A strep bacteria in it are just nonsense. It would fail its quality control if that was the case.” 

Professor Clarke also highlighted the fact that the nasal flu vaccine has been given to some school-aged children for almost a decade, without a prior increase in the rate of strep A infections. 

Dr English, a former editor of Vaccines in Practice magazine, added: “We have been using this flu vaccine for years now, and in previous years the peak in streptococcal infections has arisen in spring, not in autumn.

“Whatever the reason why we are having an increase in iGAS [invasive group A streptococcal] infections now, the nasal influenza vaccine is not likely to be the cause.”

The nasal flu vaccine was first piloted for use in school children in 2013. Over the 2021/22 flu season, all children from age two up to those in year 11 were offered the flu vaccine, with this year’s rollout concentrated in children up to year 9, though children in year 10 and year 11 may be vaccinated if there is leftover product. 

All children from reception to year 4 have been offered the vaccine in schools since 2016/17, and all children aged up to nine from 2018/19.  

Study didn’t say nasal flu vaccinations causes Strep A

Some posts and comments also imply that a study published in the scientific journal mBio is evidence that the nasal flu vaccine causes strep A infections. 

The study found that the live attenuated flu vaccine (the type given to school children) increases the likelihood of finding two types of bacteria—including two strains of streptococcus pneumoniae—in the upper respiratory tract of mice. 

However, this doesn’t mean that the nasal flu vaccine leaves children more susceptible to strep A infections—streptococcus pneumoniae and strep A are different types of bacteria. 

Streptococcus pneumoniae is the name given to a group of more than 90 different strains of bacteria which can cause non-invasive infections such as bronchitis and sinusitis, as well as invasive infections such as pneumonia and meningitis. The study looked at two of these strains. It did not find any evidence of an increased risk of severe infection or death caused by streptococcus pneumoniae in mice given the vaccine.

The study also highlights that while flu vaccination with live attenuated vaccines “primes the upper respiratory tract for increased bacterial growth and persistence of bacterial carriage” in a very similar way to an actual flu virus infection [sometimes referred to as wild-type influenza], it doesn’t increase severe bacterial disease in the lower respiratory tract in the way an actual flu virus infection can.

Professor Clarke said: “When you get flu, often what kills you [...] is a bacterial infection further down in your lungs. So you don't get that with the vaccine, but you do with wild type flu.” 

Image courtesy of Vitolda Klein