Thread by @andrewleedr

Vaccine policy was in the news lots this week regarding #JCVI's decisions on COVID vaccinations in teenagers. It's been highly contentious. Some I agree with. Some I don't. But I respect that they'll have deliberated carefully on this complex decision.
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sciencemediacentre.org/expert-reactio…

Here's my short summary of vaccine policy considerations:

The objectives of vaccination usually boil down to either:
- protecting individuals from specific diseases,
- and/or protecting populations.
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We may use vaccinations to protect selected high risk groups, who are either at high risk of getting infected (e.g. healthcare workers) or spreading the infection (e.g. kids), or if the consequences of the infection are severe (e.g. the elderly or immunocompromised).
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We may use vaccinations to contain an infection in a population by reducing the number of infections, interrupting transmission between people, generating herd immunity &/or preventing outbreaks & epidemics. We do this with Measles & Diphtheria for example.
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Lastly, we may use vaccinations to try to eradicate an infectious agent. This is difficult, costly & needs global efforts. We do this where consequences of infection are very high e.g. smallpox & polio. Needs political will, commitment, funding, international cooperation.
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Usually vaccine policy decisions consider
(1) Disease burden: not just deaths but also morbidity (short & long term) & the no. of infections,
(2) Whether immunisation is the best strategy for controlling this disease vs other possible measures.
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Key question: What's the net impact of introducing the vaccine?
Need to consider the impact on disease burden (i.e. vaccine effectiveness), vaccine safety (adverse effects?),
& feasibility & practicality of introducing it bearing in mind other vaccine/healthcare activity.
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How much disease vaccinations will prevent will depend on:
- Disease burden in the age group to be immunised
- Vaccine effectiveness & likely coverage/uptake
- Indirect effects of immunisation on disease transmission
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Need to factor in possible negative effects of vaccine programme especially re: adverse events & impact on vaccine confidence. Once you lose public trust in a vaccine it is hard to recover. Moreover, it isn't just public confidence for this vaccine but may affect others too.
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Vaccine delivery is a huge operation. Involves vaccine acquisition, transportation & storage (cold chain key!), immunisation consumables needed, training, promotion, monitoring delivery/coverage/adverse events, recording on patient records, etc... Not a one-off cost either.
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Also huge opportunity costs. Staff diverted to vaccinations are taken away from other activities. Vaccines diverted to one population group (e.g. kids) are diverted away from another (e.g. boosters for elderly). International dimension too re: equity of vaccine distribution.
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There will be other considerations too:
- ethical issues (e.g. is it right to compel care staff to have it, or to vaccinate kids to protect the elderly),
- consent issues (esp those who can't consent to it),
- wider impacts (⬇️disruption to schools, economy, protect NHS)
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Vaccine policy decisions are rarely straightforward. The UK has an established & robust system for vaccine policy decision making. Vaccine policy decisions will have to be reviewed as new evidence emerges. Ultimately, a balance of risks vs benefits for both individuals & society.