" Few older adults (over 60 years) were enrolled in clinical trials, so efficacy could not be estimated in this age group. Nevertheless, WHO is not recommending an upper age limit for the vaccine because data collected during subsequent use in multiple countries and supportive immunogenicity data suggest the vaccine is likely to have a protective effect in older persons. There is no reason to believe that the vaccine has a different safety profile in older and younger populations. WHO recommends that countries using the vaccine in older age groups conduct safety and effectiveness monitoring to verify the expected impact and contribute to making the recommendation more robust for all countries. "
สรุปง่ายๆ คือ
ถ้าอายุ 60 ขึ้น WHO เองก็ไม่มั่นใจทั้งในเรื่องของความปลอดภัยและประสิทธิภาพ เนื่องจากมีข้อมูลของประชากรกลุ่มนี้ค่อนข้างน้อยในงานวิจัย