Science

Achieving Herd Immunity Against SARS-CoV-2 Unlikely

As the UK including Scotland starts to remove the public health protections to limit the transmission of Covid-19 scientists have raised serious concerns about what seems to be the reliance now by government on ‘herd immunity.’

The American experts including Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID), part of NIH, David M. Morens, M.D., senior scientific advisor to the NIAID director, and Gregory K. Folkers, chief of staff to the NIAID director, state that achieving classical herd immunity against SARS-CoV-2 is unlikely, due to a combination of factors that include features of the virus as well as current societal dynamics.

Herd immunity which has been known to have benefits for some diseases is less successful with respiratory viruses such as influenza, which continually mutate. 

The points raised by the scientists include:

  • the virus’ ability to continually mutate to new variants
  • asymptomatic virus transmission, which complicates public health control strategies
  • the inability of prior infection or vaccination to provide durable protection against reinfection
  • suboptimal vaccination coverage
  • adherence to non-pharmacologic interventions. 

Research to develop pan-coronavirus vaccines, which could protect against multiple coronaviruses or at least multiple SARS-CoV-2 variants, remains crucial.

And say the researchers it is possible to continue with Covid-19 present without too much disruption to communities because of some immunity, vaccinations and testing.

Link: DM Morens et al. The concept of classical herd immunity may not apply to COVID-19. The Journal of Infectious Diseases DOI: 10.1093/infdis/jiac109 (2022).

Colorized scanning electron micrograph of an apoptotic cell (green) heavily infected with SARS-COV-2 virus particles (yellow), isolated from a patient sample. Image captured at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. Image credit:

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  1. Herd immunity can happen when, once having had a disease, you can’t catch it again. That isn’t the case with Covid. It keeps changing, and we can catch the new variants. So herd immunity doesn’t apply.

    The heavily infected apoptotic cell is an ugly little spud, isn’t it? The stuff that Science Fiction films are made of.
    Hang on a minute…..we’re living in one …but it’s fact, not fiction.