Benefit-risk analysis of health benefits of routine childhood immunisation against the excess risk of SARS-CoV-2 infections during the Covid-19 pandemic in Africa

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Benefit-risk analysis of health benefits of routine childhood immunisation against the excess risk of SARS-CoV-2 infections during the Covid-19 pandemic in Africa

https://cmmid.github.io/topics/covid19/EPI-suspension.html

Summary
Background: National immunisation programmes globally are at risk of suspension due to the severe
health system constraints and physical distancing measures in place to mitigate the ongoing
COVID-19 pandemic. Our aim is to compare the health benefits of sustaining routine childhood
immunisation in Africa against the risk of acquiring SARS-CoV-2 infections through visiting routine
vaccination service delivery points.

Methods: We used two scenarios to approximate the child deaths that may be caused by
immunisation coverage reductions during COVID-19 outbreaks. First, we used previously reported
country-specific child mortality impact estimates of childhood immunisation for diphtheria, tetanus,
pertussis, hepatitis B, Haemophilus influenzae type b, pneumococcal, rotavirus, measles, meningitis
A, rubella, and yellow fever (DTP3, HepB3, Hib3, PCV3, RotaC, MCV1, MCV2, MenA, RCV, YFV) to
approximate the future deaths averted before completing five years of age by routine childhood
vaccination during a 6-month Covid-19 risk period without catch-up campaigns. Second, we analysed
an alternative scenario that approximates the health benefits of sustaining routine childhood
immunisation to only the child deaths averted from measles outbreaks during the Covid-19 risk
period. The excess number of infections due to additional SARS-CoV-2 exposure during immunisation
visits assumes that contact reducing interventions flatten the outbreak curve during the Covid-19
risk period, that 60% of the population will have been infected by the end of that period, that
children can be infected by either vaccinators or during transport and that upon child infection the
whole household would be infected. Country specific household age structure estimates and age
dependent infection fatality rates are then applied to calculate the number of deaths attributable to
the vaccination clinic visits. We present benefit-risk ratios for routine childhood immunisation
alongside 95% uncertainty range estimates from probabilistic sensitivity analysis.

Findings: For every one excess Covid-19 death attributable to SARS-CoV-2 infections acquired during
routine vaccination clinic visits, there could be 140 (37 – 549) deaths in children prevented by
sustaining routine childhood immunisation in Africa. The benefit-risk ratio for the vaccinated
children, siblings, parents or adult care-givers, and older adults in the households of vaccinated
children are 53,000 (3,400 – 21,865,000), 47,000 (3,000 – 19,340,000), 2,000 (410 – 12,000), and 154
(40 – 617) respectively. In the alternative scenario that approximates the health benefits to only the
child deaths averted from measles outbreaks, the benefit-risk ratio to the households of vaccinated
children is 5 (1 – 21) under these highly conservative assumptions and if the risk to only the
vaccinated children is considered, the benefit-risk ratio is 2,000 (131 – 839,000).

Interpretation: Our analysis suggests that the health benefits of deaths prevented by sustaining
routine childhood immunisation in Africa far outweighs the excess risk of Covid-19 deaths associated
with vaccination clinic visits. However, there are other factors that must be considered for strategic
decision making to sustain routine childhood immunisation in African countries during the Covid-19
pandemic. These include logistical constraints of vaccine supply chain problems caused by the
Covid-19 pandemic, reallocation of immunisation providers to other prioritised health services,
healthcare staff shortages caused by SARS-CoV-2 infections among the staff, decreased demand for
vaccination arising from community reluctance to visit vaccination clinics for fear of contracting
SARS-CoV-2 infections, and infection risk to healthcare staff providing immunisation services as well
as to their households and onward SARS-CoV-2 transmission into the wider community.
Funding: Gavi, the Vaccine Alliance and Bill & Melinda Gates Foundation (OPP1157270)

https://cmmid.github.io/topics/covid19/EPI-suspension.html

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