OK Chris so you're good at cut and paste - but it would save me a lot of time if you could include links to your sources - but have managed to track them down anyway.
I don't disagree with a lot of the suggestions about how to boost your immune system - but I take them with a pinch of salt when they are listed on a site whose purpose is to sell the very supplements named in the list.
Top 20 ways to boost your immunity to colds and flu without using vaccines
As for the Cochrane collaboration study not only have I read the article that you cut and pasted which is available on several websites but I have also read the original Cochrane study and I will now cut and paste from that...
The results of this review seem to discourage the utilisation of vaccination against influenza in healthy adults as a routine public health measure. As healthy adults have a low risk of complications due to respiratory disease, the use of the vaccine may be only advised as an individual protection measure against symptoms in specific cases. [The study only looked at results from healthy adults between 16 and 65. These are not the ones currently being offered the flu vaccine in the UK.]
The content and results of previous versions of this review have been extensively misquoted especially in public policy documents. Two types of common misquotes are the generalisation of evidence from this review to all age and risk groups and the generalisation of estimates of effect to all outcomes (especially complications and deaths). The misquotes then assume that the performance of influenza vaccines is uniform across all age groups and from symptom prevention to all outcomes. Both generalisations are not supported by any evidence and seem to originate from the desire to use our review to support decisions already taken. The misquotes appear to be based on both the abstract and Plain language summary (which is what you would expect from a superficial reading of the review by people with a specific agenda).
The universal immunisation of healthy adults should achieve a number of specific goals: reducing the spread of the disease, reducing the economic loss due to working days lost and reducing morbidity and hospitalization. None of the studies included in the review presented results evaluating the ability of this vaccination to interrupt the spread of the disease. Some studies presented data on reduction of working days lost and showed a very limited effect. Similarly a very limited effect was found on morbidity and no effect was found on hospitalization. Given the limited availability of resources for mass immunisation, the use of influenza vaccines should be primarily directed where there is clear evidence of benefit. [So it is currently offered only to the over-65s and others with various health problems.]
We are not aware of other systematic reviews on this topic. [So more work needs to be done.]