Definition of vaccination immunisation have changed
Executive summary
US immunization guidance has shifted in 2025 from blanket, population-level directives toward more “individual-based decision‑making” for some vaccines: the CDC updated its schedules in October to apply shared clinical decision‑making for COVID‑19 and to separate varicella from combined MMRV for toddlers [1] [2]. In December 2025 ACIP moved to abandon universal newborn hepatitis B vaccination in favor of maternal-risk–based discussions, marking the most consequential federal change this year and prompting intense debate [3] [4].
1. What “definition” of vaccination and immunisation has actually changed?
The technical definition of vaccination — giving a biologic to elicit immune protection — has not been redefined in core public‑health references such as WHO or ECDC; they continue to describe vaccination as protection that uses the body’s defenses to build resistance to infections [5] [6]. What has changed in practice in the United States is policy framing: CDC schedules now explicitly use “individual‑based decision‑making” (also called shared clinical decision‑making) for certain vaccines rather than universal, one‑size‑fits‑all recommendations [1].
2. How the US policy shift looks on the ground
In October 2025 the CDC revised its adult and child immunization schedules to apply individual‑based decision‑making to COVID‑19 vaccination and to make varicella a standalone vaccine for toddlers rather than part of an MMRV combination [1] [2]. In early December, ACIP voted to abandon universal newborn hepatitis B vaccination in favor of a more targeted, mother‑informed approach — a policy reversal that news organizations describe as the most significant federal vaccine‑policy change in years and that has triggered immediate controversy [3] [4].
3. Why authorities say they made these changes
Officials cite evidence and risk‑benefit calculations. CDC materials state that individual decision‑making for COVID‑19 reflects differing risk profiles — benefits are greatest for those at increased risk for severe disease and lower for otherwise healthy younger adults — and that the change aligns guidance with shared clinical judgment between providers and patients [1]. HHS and CDC framed the varicella decision partly on safety data (noting higher febrile‑seizure risk with the combination vaccine) and argued informed consent is being restored to vaccine conversations [2].
4. Why critics warn these moves could be risky
Public health voices and news outlets warn that dismantling universal recommendations can erode population protection and reverse long‑term gains — for example, hepatitis B infant immunisation drove a 99% decline in reported acute pediatric hepatitis B from 1990–2019 according to reporting cited by The Guardian [7]. CNN and NPR report alarm among scientists and parents who fear individualizing newborn hepatitis B could increase vulnerability and complicate clinic workflows [4] [3].
5. Broader context: not an isolated US trend
International public‑health organizations continue to emphasize vaccination as a core preventive tool: WHO materials reiterate vaccination’s role in saving millions of lives and remain focused on universal coverage goals [5] [8]. Scientific journals note that disruptions in advisory processes can unsettle guidance and that independent evidence review remains essential for decisions about respiratory virus immunisation in 2025–26 [9].
6. Hidden agendas, political currents and institutional friction
Reporting links the timing and scope of changes to broader shifts inside HHS and CDC leadership: journalists note Health Secretary Kennedy’s prior actions, an HHS memo pushing reevaluations, and concerns that advisory independence has been weakened — elements that shape both the rationale for change and public distrust [3] [10] [4]. The HHS press framing—“Informed consent is back”—signals an ideological turn toward individualized care that critics say may prioritize personal choice over collective protection [2].
7. What’s missing from available reporting
Current sources provide rationale, policy language and political context but do not present comprehensive, long‑term impact data on the effects of these schedule shifts; available sources do not mention post‑policy national outcomes such as changes in hepatitis B incidence among infants after the ACIP decision (not found in current reporting). They also do not fully document internal ACIP deliberations or all evidence reviewed at the meeting beyond summary points [3] [4] [1].
8. Takeaway for clinicians, parents and policymakers
Clinicians must prepare to practice more shared decision‑making for vaccines specified as individual‑choice and to document risk discussions [1]. Parents should expect more conversations about risks and benefits, particularly for COVID‑19, varicella, and newborn hepatitis B [1] [2] [3]. Policymakers should anticipate debate over population‑level impacts and fund independent evaluations to monitor vaccine coverage and disease trends as guidance evolves [9].