Increasing seroprevalence but waning herd immunity against measles after elimination: Longitudinal seroepidemiology of measles in Osaka Prefecture, Japan, 2003–2020

Resurgent global measles: A threat to Australia, New Zealand and Pacific Island Countries

“…In elimination settings, like Australia, New Zealand and many Pacific nations, it is important to be aware of ‘modified measles’. This presents with a less florid rash, less or absent cough and a more subtle prodrome, and results from a ‘breakthrough infection’ 4,20,21 . Breakthrough measles infections are reasonably uncommon, but can occur due to an inadequate response at the time of vaccination (primary failure) or where initially protective immunity has waned over time (secondary failure) 20 .…”

“…Breakthrough measles infections are reasonably uncommon, but can occur due to an inadequate response at the time of vaccination (primary failure) or where initially protective immunity has waned over time (secondary failure) 20 . Secondary failure may become more common in post‐elimination settings where there is absence of regular immune‐boosting from circulating wild‐strain virus 21,22 . Virus burden and transmissibility appear to be lower in modified measles, but onward transmission may still occur, requiring isolation of cases and public health responses 20,23 …”

“…This presents with a less florid rash, less or absent cough and a more subtle prodrome, and results from a 'breakthrough infection'. 4,20,21 Breakthrough measles infections are reasonably uncommon, but can occur due to an inadequate response at the time of vaccination (primary failure) or where initially protective immunity has waned over time (secondary failure). 20 Secondary failure may become more common in post-elimination settings where there is absence of regular immune-boosting from circulating wild-strain virus.…”

“…20 Secondary failure may become more common in post-elimination settings where there is absence of regular immune-boosting from circulating wild-strain virus. 21,22 Virus burden and transmissibility appear to be lower in modified measles, but onward transmission may still occur, requiring isolation of cases and public health responses. 20,23 Thirdly, undertake the correct confirmatory tests.…”

Long-term waning of vaccine-induced immunity to measles in England

“…Occasional outbreaks were also reported in highly vaccinated groups 7,8 , leading to concerns over waning of measles immunity among adults vaccinated during their childhood 9 . Immunological studies from Canada 10 , Japan 11 , and Czechia 12 pointed towards waning of antibodies in young adults who had been vaccinated more than 20 years prior, while no decrease was observed in previously infected individuals 13 . Young vaccinated adults had little exposure to measles in near-elimination settings, showing that waning of vaccine-induced immunity may be related to the time since the end of endemic transmission 14 .…”