NZNO signs up to scientific approach

February 1, 2021

The board has agreed to adopt the “John Snow memorandum”, a science-based response to COVID-19, as NZNO policy.

The memorandum is named after an epidemiologist who traced the source of a London cholera outbreak in 1854. It was a response to a herd immunity approach suggested late last year in Great Barrington, Massachusetts, board member Simon Auty told the board.


In October 2020, the “Great Barrington declaration”1 challenged lockdown measures, urging instead a “focused protection” approach. Easing restrictions on low-risk groups, some epidemiologists argued, would lead to herd immunity.


But an opposing group of experts launched the John Snow memorandum, warning herd immunity was a “dangerous fallacy unsupported by scientific evidence”.2 Such a strategy would result in recurring epidemics, the group of researchers wrote in an open letter to medical journal The Lancet in October.2

In New Zealand, the “COVID Plan B” group promoted a herd immunity approach. This failed to consider the “precarious state of New Zealand’s health-care system, the unique vulnerabilities of Māori and Pasifika community in New Zealand and the probability of spread from New Zealand to the Pacific Islands”, Auty said in his proposal for NZNO to adopt the memorandum.

Many prominent New Zealanders in epidemiology and infection control had signed the memorandum, which aligned with NZNO’s strategic plan and the national COVID-19 response strategy, Auty said. “The John Snow memorandum provides a solid scientific rationale to base any of our COVID response policies and any member advocacy on around this issue.”



  1. Sample, I. (2020). Scientists call for herd immunity Covid strategy for young. The Guardian.
  2. Finucane, M. (2020), Boston Researchers join letter in The Lancet rejecting herd immunity strategy. The Boston Globe.

This article has been written from reports and minutes taken from the December 2020 board of directors meeting.