Wednesday, November 25, 2015

UK ONS: 2014-15 Excess Winter Mortality Highest Since 1999

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# 10, 746

 

Tying in nicely to my last blog  CPR As A Basic Holiday Survival Skill (which I wrote before seeing this report), is a statistical bulletin released today from the UK’s Office of National Statistics called:.

 

Statistical bulletin: Excess Winter Mortality in England and Wales 2014/15 (Provisional) and 2013/14 (Final)

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Main points

  • An estimated 43,900 excess winter deaths occurred in England and Wales in 2014/15; the highest number since 1999/00, with 27% more people dying in the winter months compared with the non-winter months.
  • The majority of deaths occurred among people aged 75 and over; there were an estimated 36,300 excess winter deaths in this age group in 2014/15, compared with 7,700 in people aged under 75.
  • There were more excess winter deaths in females than in males in 2014/15, as in previous years. Male excess winter deaths increased from 7,210 to 18,400, and female deaths from 10,250 to 25,500 between 2013/14 and 2014/15.
  • Respiratory diseases were the underlying cause of death in more than a third of all excess winter deaths in 2014/15.
  • The excess winter mortality index was highest in the South West in 2014/15 and joint lowest in Yorkshire and The Humber, and Wales.

Get all the tables for this publication in the data section of this publication .

 

The last time EWM (Excess Winter Mortality) rates were this high in the UK was in 1999, a year which saw an unusually severe flu season both in the UK and the United States.   The report blames a less-than-optimal flu vaccine match, and a severe H3N2 flu season (which hits older people harder than H1N1), for the spike. 


From the report:

Levels of influenza in 2014/15 were higher than recent years, as were peak intensive care numbers, but were lower than 2010/11 which saw very high levels of influenza (Public Health England, 2015). Despite this, EWM was higher in 2014/15 than in 2010/11. In 2010/11 the predominant influenza virus was A(H1N1), as in 2013/14. One reason for the reduced EWM in 2010/11 when compared with 2014/15, is because the predominant strain of influenza in 2014/15 was particularly virulent in older people, an already at-risk group, whilst in 2010/11 the predominant strain of influenza was a particular problem in younger people and had less impact on the elderly (Public Health England, 2014). In addition to this, the influenza vaccine in 2010/11 was around 50% effective (Public Health England, 2011), compared with the 34% effectiveness in 2014/15. Vaccine uptakes were similar in 2014/15 to previous years, though uptake was slightly lower than in previous years in those under 65 in a clinical risk group (Public Health England, 2015).

 


While some of the UK papers are going for hyperbolic headlines like:

 

Ineffective flu vaccine causes the number of excess winter deaths to TRIPLE in a year - to the highest level this century – Daily Mail.


Perhaps the bigger story is how many lives have been spared over the past 15 years when the flu vaccine was a reasonably good match . . . and how many more lives we could save if we had a more effective flu vaccine for the elderly, and a greater uptake among vulnerable populations.

 

While most of the `excess winter deaths’ are attributed on death certificates to other causes – pneumonia, heart attack, stroke, etc. – we know these rates go up and down with the severity of each year’s flu season, and with the effectiveness of the each year’s flu vaccine.


Hence the spate of recent studies showing that flu vaccination can reduce the rate of heart attacks, and other cardiovascular events, in the elderly (see UNSW: Flu Vaccine Provides Significant Protection Against Heart Attacks).


Unfortunately, the flu vaccine’s effectiveness tends to drop the older the recipient, sometimes due to a less robust immune system, and sometimes due to medications (see JID: Statins & Flu Vaccine Effectiveness), or other chronic health conditions.

 

For those over 65 there is a High-Dose flu vaccine option currently available  that contains 4 times the normal amount of antigen; 60 µg of each of the three recommended strains, instead of the normal  15 µg (see MMWR On High Dose Flu Vaccine For Seniors).

 

While ACIP and the CDC have not expressed a preference for using a high-dose vaccine in those > 65, in their Fluzone High-Dose Seasonal Influenza Vaccine Q&A they write;

 

Does the higher dose vaccine produce a better immune response in adults 65 years and older?

Data from clinical trials comparing Fluzone to Fluzone High-Dose among persons aged 65 years or older indicate that a stronger immune response (i.e., higher antibody levels) occurs after vaccination with Fluzone High-Dose. Whether or not the improved immune response leads to greater protection has been the topic on ongoing research. A study published in the New England Journal of Medicine indicated that the high-dose vaccine was 24.2% more effective in preventing flu in adults 65 years of age and older relative to a standard-dose vaccine. The confidence interval for this result was 9.7% to 36.5%).

 

But even at a reduced vaccine effectiveness, some protection beats no protection at all.  And there is some evidence that even when it doesn’t prevent infection, the flu vaccine may reduce the severity of illness (CDC: Flu Shots Reduce Hospitalizations In The Elderly).

 

As regular readers of this blog already know, I get one every year. And while I sometimes worry that the benefits (and effectiveness) of the flu vaccine are oversold, flu vaccines remain our best protection against a virus that is estimated to kill a half million people around the globe each year.   

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