We are sure you will be aware, and many of your patients aware, of the failings of last year's flu vaccine. So why bother this year?
How well the flu vaccine works can range from season to season and is dependent on the similarity or 'match' between the circulating flu viruses and the influenza strains in the flu vaccine itself.
The influenza viruses in the seasonal flu vaccine are recommended by the World Health Organisation (WHO) each year using surveillance-based forecasts regarding which viruses are most likely to cause illness in the coming season.
Flu vaccine protection
Studies show that vaccination reduces flu-related hospitalisations among adults of all ages by 70% and even more in those over 50. Vaccination helps protect women during pregnancy and their babies for up to six months after they are born. Estimates of the annual number of deaths attributable to flu in the UK vary with an average of around 8,000 per year.
Flu vaccination is strongly recommended for those in at risk groups such as asthmatics, those with chronic health conditions and those over 65. Although the current flu vaccine is not perfect, the overall evidence supports the public health benefit of vaccination.
The vaccine contains three or four killed flu viruses so even when there is a less than an ideal match against one virus, the vaccine may protect against the others.
Since 2013, two- and three-year-olds have been eligible for vaccination with a newly available live attenuated vaccine. Children are the source of many influenza infections and quickly pass the virus to elderly relatives with substantial consequences.
Worldwide there are between 250,000 and 500,000 flu deaths per year. In a typical flu season between 3m and 5m people will have a serious case of influenza.
Flu jab effectiveness
Regarding last year’s flu vaccine (2014/15) based on the recommendations from the WHO, vaccine production started in the second quarter of the year ready for the vaccination campaign in the third quarter; it takes six months to manufacture. However, the virus selected for the vaccine against the most serious strain (H3) did not match the virus circulating that winter, there was a mismatch. The vaccine was estimated to work in just 3% of cases, compared with typical past effectiveness.
According to the CDC, more than two-thirds of influenza A (H3N2) viruses in circulation were mismatched from the vaccine. UK based studies confirmed this.
Nick Phin, the director of the Centre for Infectious Disease at Public Health England, said that officials had known about the mismatch between the strain in the vaccine and the new mutation since last summer, when it was detected in Australia. Talking to the BBC Today programme he called for a 'better vaccine' offering protection against a wider range of strains to help avoid a similar situation in future.
Dr Richard Pebody, PHE’s head of flu surveillance, said: 'Throughout the last decade, there has generally been a good match between the strains of flu in the vaccine and those that subsequently circulate, so it’s crucial that these results do not discourage people in at-risk groups from having flu vaccination now, or in the future.
'Our findings also mean that the early use of antivirals to treat and help prevent serious cases of flu in vulnerable patients is even more important this season.'
Unfortunately it is believed that the mortality rate in the UK due to the mismatch of the vaccine increased by up to 50%. What this tells us is that when the flu vaccine is properly matched, it is effective in saving lives and therefore those in at risk groups and children should be encouraged to get the vaccine. However when the vaccine is mismatched more people die. The need for a better influenza vaccine is clear, in the meantime the current vaccine does save lives.
- Dr Martin Johnson is senior medical director at hVivo Ltd and RCGP chronic pain lead. Dr Rob Lambkin-Williams is executive scientific adviser at hVivo Ltd.
Picture: Jim Varney