New research from Burnet Institute shows faster vaccination responses to outbreaks of infectious diseases could prevent a large proportion of illness and death in low- and middle-income countries, even when ideal response targets are not fully met.

The study modelled the impact of meeting the 7-1-7 target – a global target gaining traction allowing countries to assess their readiness to detect and respond to outbreaks and improve their performance.

The target measures whether outbreaks are detected within 7 days of emergence, notified to health authorities within 1 day, and early response actions (including outbreak vaccination) initiated within another 7 days.

The modelling found that initiating outbreak response immunisation within 15 days of the emergence of measles, cholera, yellow fever or meningococcal meningitis could prevent:

• up to 80 per cent of cases in cholera outbreaks

• around 35 per cent of cases in meningococcal meningitis outbreaks

• up to 55 per cent of measles cases, depending on routine vaccine coverage

• up to 35 per cent of yellow fever cases, depending on local risk and environmental conditions

The study found that even if a 15-day response cannot be achieved, delayed vaccination remains far more effective than no vaccination, and incremental improvements in response time can significantly reduce cases.

“Our findings show that speed really matters when it comes to outbreak response,” said Burnet health modeller, Dominic Delport.

“When vaccination is started in the early stages of an outbreak it can effectively disrupt transmission and protect much of the population from getting sick, particularly in high-risk settings.”

The research used agent-based models calibrated against data from 203 real-world outbreaks across low- and middle-income countries since 2000. The models compared current average response times – which often stretch to several months – with faster response scenarios.

The study also found the impact of faster responses varies by location, with the greatest benefits seen in higher-risk environments where there are lower levels of routine vaccinations.

This suggests that pairing faster response targets with context-specific risk assessments could help countries prioritise limited resources when multiple outbreaks happen at once.

“Strengthening outbreak detection, response systems and improving the timeliness of vaccination campaigns is an effective way to reduce the burden of vaccine-preventable disease outbreaks,” Dr Delport said.

“More timely vaccination responses can also reduce the risk of outbreaks growing large enough to cause significant social and economic disruptions.”