Few subjects in medicine have become as polarized as vaccination. The public debate is increasingly framed as a binary choice: either one trusts vaccines or one trusts natural immunity. Yet immunology does not operate in slogans. The biological value ─ and potential limitations ─ of any immunization strategy depend on context: the pathogen, the stage and intensity of an epidemic, the immune status of the host, the nature of the immune response induced and the extent to which that response prevents infection and transmission rather than merely disease.
This presentation argues that natural immunity and vaccination should therefore not be treated as mutually exclusive principles. During an epidemic or pandemic caused by an acute, self-limiting viral infection, for example, the first priority should be to preserve and strengthen the host’s broad first line of immune defense while reducing infection pressure. Innate immunity provides immediate, pathogen-nonspecific protection while infection-induced adaptive immunity develops. When the latter is capable of efficiently clearing infection and curtailing transmission, its accumulation across the population can generate protective herd immunity. By contrast, a vaccine-induced immune response that protects primarily against disease but does not reliably prevent infection or onward transmission may, when deployed during intense circulation of a rapidly evolving virus, impose population-level immune selection pressure without sterilizing transmission. In my interpretation, this distinction is central to understanding viral immune escape and illustrates why the timing and epidemiological context of vaccination matter as much as vaccine efficacy at the individual level.
This does not imply that vaccination and natural immunity are antagonistic. Once an epidemic has subsided, preventive vaccination of immunologically naïve individuals can protect those individuals while helping preserve herd immunity as naturally acquired protective immunity gradually erodes through demographic turnover. This consideration becomes particularly important for infections capable of causing substantial mortality in susceptible children or immunocompromised individuals. In such circumstances, vaccination of the immunologically naïve fraction ─ ideally with an approach capable of reproducing the protective qualities of natural infection without the risks associated with pathogen replication ─ may be preferable to maintaining protective herd immunity through recurrent natural infection.
A neglected third component may offer a bridge between these apparently opposing positions: trained innate immunity. It is now established that innate immune cells can undergo durable functional adaptation through epigenetic and metabolic reprogramming, producing altered responsiveness to subsequent environmental challenges. The important question is therefore no longer whether innate immunity can be trained, but how far such training can safely be directed ─ from nonspecific natural antibodies and cytokine-mediated antiviral resistance toward enhanced pathogen-nonspecific cell-mediated innate immune surveillance involving innate immune cells (e.g., natural killer [NK] cells, innate lymphoid cells, monocytes/macrophages and dendritic cells). In other words: Can immunization science create ‘gain’ without requiring biological ‘pain’?
The deeper message extends beyond vaccines. Scientific progress is obstructed when complex biological questions are reduced to ideological binaries. Protective herd immunity, viral immune escape and trained innate immunity must be considered together. Replacing the pro-vax/anti-vax confrontation with a context-dependent immunological framework may reveal that natural immunity and vaccination are not competing dogmas but complementary tools whose appropriate use depends on when, where, how and in whom they are applied ─ and on the broader demographic, epidemiological and health context of the population..
Keywords: natural immunity; vaccination; protective herd immunity; viral immune escape; trained innate immunity; immunization strategy
Geert Vanden Bossche received his DVM from the University of Ghent, Belgium, and his PhD degree in Virology from the University of Hohenheim, Germany. He held adjunct faculty appointments at universities in Belgium and Germany. After his career in Academia, Geert joined several vaccine companies (GSK Biologicals, Novartis Vaccines, Solvay Biologicals) to serve various roles in vaccine R&D as well as in late vaccine development.
Geert then moved on to join the Bill & Melinda Gates Foundation’s Global Health Discovery team in Seattle (USA) as Senior Program Officer; he then worked with the Global Alliance for Vaccines and Immunization (GAVI) in Geneva as Senior Ebola Program Manager. At GAVI he tracked efforts to develop an Ebola vaccine. He also represented GAVI in fora with other partners, including WHO, to review progress on the fight against Ebola and to build plans for global pandemic preparedness.
Back in 2015, Geert scrutinized and questioned the safety of the Ebola vaccine that was used in ring vaccination trials conducted by WHO in Guinea. His critical scientific analysis and report on the data published by WHO in the Lancet in 2015 was sent to all international health and regulatory authorities involved in the Ebola vaccination program. After working for GAVI, Geert joined the German Center for Infection Research in Cologne as Head of the Vaccine Development Office. He is at present primarily serving as a Biotech / Vaccine consultant while also conducting his own research on Natural Killer cell-based vaccines.
Email: info@voiceforscienceandsolidarity.org
.svg){kind=small}
