For the past two flue seasons, exactly the same strains have been included by the influenza vaccine for the past two flue seasons but according to data available, the vaccine availed this year was very ineffective and the strains are circulating no more.

Vaccines and Related Biological Products

In this regard, both trivalent and quadrivalent vaccines available in US will be overhauled totally in line with the recommendations of the Vaccines and Related Biological Products Advisory Committee. The exercise undertaken on a yearly basis for predicting the influenza viruses that are going to be a threat this coming winter will be based on global monitoring even though this isn’t expected to be perfect.

For the winter period of 2014 to 2015, it has been realized that the vaccine is very effective and considerably reduces the likelihood of seeking influenza treatment by 19% in comparison to the more than 60% in most years. The vaccine given in this season wasn’t unable to offer protection against the predominant A strain. Ideally, the H3N2 strains have been associated with causing worse illnesses and leads to higher mortality. The so called Switzerland strain was in circulation barely and only comprised of just 1 percent of the viruses detected when the US vaccine recommendations were formulated by FDA in February 2014. In fact, it would be later realized in late summer that the main agent causing illness was the Switzerland strain.

Older Americans hit by low effectiveness

The vaccine showed very disappointing results as far as its effectiveness is concerned and the older Americans suffered really hard compared to the rest of the population. Also, a big number of pediatric cases have been reported as well and nearly 100 deaths have also been reported in children as well. An interesting investigation was that patients aged above 65 years showed a higher rate of vaccine effectiveness compared to the rest of the age groups by 24 percent overall in comparison to 8 percent for those aged between 18 and 49 years and 18 percent for those aged between 9 and 17 years.

H3N2 which is a more deadly vaccine had an effectiveness of 28 percent for people aged above 65 years. Though February 21, about 14000 people have been hospitalized. In most of the age groups, it became apparent that the hospitalizations were at par with three flu seasons reported previously. For the Americans who were aged above 65 years, this was the highest rate recorded since CDC started surveillance of the hospitalizations in 2005. After January 1, there was a peak in the flu mortality even though this was still above the threshold of the epidemic by February 21. Influenza has been causing many deaths among the young and older people alike in America with H3N2 being the most notorious strain.