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Rapid response to:

Head To Head

Should countries aim for elimination in the covid-19 pandemic?

BMJ 2020; 370 doi: (Published 09 September 2020) Cite this as: BMJ 2020;370:m3410

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Rapid Response:

The COVID-19 elimination debate – needs to use correct data

Dear Editor

Many of the arguments raised by Thornley et al in the BMJ’s recent head-to-head debate (BMJ 2020;370:m3410) against taking an elimination approach to COVID-19 are in our view misleading and incorrect. In particular, their mistaken assertion that the infection fatality risk (IFR) for COVID-19 is “similar to that for seasonal flu”.

Research conducted in New Zealand (NZ) and internationally suggests that the IFR for COVID-19 is typically at least an order of magnitude higher than for seasonal flu. The most detailed study of seasonal influenza mortality in NZ to date estimated average annual mortality of 13.5 (95%CI 13.4, 13.6) per 100,000 population [1]. Furthermore, the proportion of the NZ population infected with influenza in a year has been measured from a seroconversion study at 35% (95%CI: 32%-38%) [2]. Combining these figures suggests an IFR for seasonal influenza of about 0.039% (ie, 13.5/35,000) in NZ. This seasonal influenza IFR is 17 times lower than that estimated for COVID-19 at 0.68% [3] and 0.65% [4], based on international data (there have been too few COVID-19 cases in NZ to produce an IFR estimate).

Furthermore, as Lee points out in the same debate article, there is growing evidence for long-term health impacts from COVID-19 which need to be considered when comparing the elimination strategy with the alternative suppression or mitigation approaches [5].

It is reasonable to debate the COVID-19 elimination strategy as it is likely that the feasibility of achieving this goal will vary by country circumstances. That is, it seems hard for countries with large land borders, federal systems, and dysfunctional governments; but more feasible for island nations such as New Zealand (NZ) [6]. But such debates need to use correct data.

1. Khieu TQT, Pierse N, Telfar-Barnard LF, et al. Modelled seasonal influenza mortality shows marked differences in risk by age, sex, ethnicity and socioeconomic position in New Zealand. J Infect 2017;75(3):225-33. doi: 10.1016/j.jinf.2017.05.017 [published Online First: 2017/06/06]
2. Huang QS, Bandaranayake D, Wood T, et al. Risk Factors and Attack Rates of Seasonal Influenza Infection: Results of the Southern Hemisphere Influenza and Vaccine Effectiveness Research and Surveillance (SHIVERS) Seroepidemiologic Cohort Study. J Infect Dis 2019;219(3):347-57. doi: 10.1093/infdis/jiy443 [published Online First: 2018/07/18]
3. Meyerowitz-Katz G, Merone L. A systematic review and meta-analysis of published research data on COVID-19 infection-fatality rates. medRxiv 2020;(7 July). doi:
4. Centers for Disease Control and Prevention. Coronavirus Disease 2019 (COVID-19): Pandemic planning scenarios. 2020;(10 July).
5. Mahase E. Covid-19: What do we know about "long covid"? BMJ 2020;370:m2815. doi: 10.1136/bmj.m2815 [published Online First: 2020/07/16]
6. Baker MG, Wilson N, Anglemyer A. Successful elimination of Covid-19 transmission in New Zealand. N Engl J Med 2020;(7 August) doi:101056/NEJMc2025203 https://wwwnejmorg/doi/101056/NEJMc2025203?url_ver=Z3988-2003&rfr_id=ori... 2020 doi: 10.1056/NEJMc2025203 [published Online First: 2020/08/09]

Competing interests: No competing interests

16 September 2020
Michael G. Baker
Professor of Public Health
Professor Nick Wilson
University of Otago, Wellington
23 Mein Street, Newtown, Wellington, New Zealand