Page 77 - Htain Manual

given vaccine using sub-optimal dose or incorrect route. Hence, the effectiveness may be

lower than the efficacy reported in RCT. For an EE which is dealing with a policy question of

whether to introduce the vaccine in national immunization schedule, the data on pragmatic

real-world effectiveness is more useful than efficacy.

Secondly, several trials may be done for determining clinical effectiveness in terms of

outcomes which may be perfectly rational to a particular health condition, but may not solve

the needs for an EE. For example, a RCT for determining clinical effectiveness of new anti-

hypertensive drug compared to the existing treatment measured its effectiveness in terms of
reduction in blood pressure. However, the appropriate outcome measure which is

recommended for an EE is a generic utility based measure such as quality adjusted life year

(QALY). This is so because it allows comparison of efficiency across a range of different types
of interventions applicable for different diseases in different types of patient population.

Hence again, RCT falls short of providing solution for EE.

Thirdly, on grounds of feasibility, most of the trials are run for short period of time

which is appropriate enough to document clinical effectiveness. However, an EE aims at
measuring all the costs and consequences which are a result of the intervention. For example,

a clinical trial which may be carried out for a hemophilus influenza type ‘b’ (Hib) vaccine (given

to children at 6,10 and 14 weeks of age) which offers protection against pneumonia and

meningitis due to the said organism, measured the episodes of Hib disease among vaccinated

and unvaccinated cohorts during a 1 year period following vaccine administration. While this
may be sufficient for measuring the vaccine efficacy, however, the protection against Hib

disease continues as long as child is susceptible, which is generally about 5 years, and to a

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lesser degree as long as 15 years . Hence there is a reduction of disease episodes much longer
than the trial period. So, while a trial in this case may measure all costs accurately – as all

costs related to vaccination are incurred in year 1, it underestimates the health benefits as

well as cost savings (due to decrease in treatment costs). In order to overcome this problem

of measuring benefits, RCTs will need to be extended till the time intervention continues to

be beneficial, so that all costs and consequences are valued credibly. However, this can
sometimes become unfeasible. For example, in case of a preventive intervention such as

vaccine for human papillomavirus (HPV) to protect against cervical cancer among women,

while the vaccination is recommended to be done around the age of 10-12 years, reduction

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