E-DRUG: Pneumococcal vaccines effective and safe (2)
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Dear E-druggers,
In a national immunization campaign a minimum level of immunity in the target population is needed to achieve reduction, or elimination / eradication of the disease. Firstly surveillance needs to point out whether the disease is a priority burden. The immunity level achievable is a product of vaccine efficacy and vaccine uptake in the target population. If uptake is unknown, or low, a high vaccine efficacy will not necessarily mean the same as effectiveness, especially not where we count on herd immunity (human reservoir).
Thus as a public good, a private-out-of-pocket cost as high as 12,000 rupees is a barrier for uptake in a national program and should ideally be removed. The minimum immunity level required is determined by risk of transmission, duration of infection and average number of contacts.
Maybe not surprisingly even with a VE of 90%, the two (achievable immunity and desired immunity level) do not always necessarily meet.
Effectiveness needs to monitored post-implementation on population level (incidence and sero-prevalences subtypes, susceptibility). Side effects: e.g. asthma, if the occurrence of asthma is only measured in the vaccine group, but not in a control group, you cannot state that increase associates with vaccine. If asthma symptoms are a reason to vaccinate a child against pneumococcal infection the intervention group is biased. If ‘wheezing’ is counted as asthma a more specific case definition is required to do a useful study.
So I was wondering whether the issue has more to do with how to implement a national vaccination than the efficacy/safety of the vaccine itself. I suspect there is no clarity whether vaccination against pneumococcal infection under 5 is a priority in India but if so, government policy should ensure maximum uptake instead of leaving it up to private practitioners and private patients. Otherwise it seems to remain a limited and probably cost-ineffective matter of protecting individuals only.
With kind regards,
Pascal Verhoeven
Pharmacist, studying public health
verhoeven.pascal@gmail.com