While organised mammography screening programs were being gradually introduced across various countries, researchers could study the impact of screening on breast cancer mortality by comparing mortality in areas with and without screening. Now that screening has been fully implemented in most Western countries, researchers can only compare women who participate in screening with those who do not participate.
Women who do not participate in screening may seem to be a good choice as a comparison group, as they are not affected by screening. But the question is: can non-participants reflect how breast cancer mortality would have developed in women in general without the introduction of screening?
We need to be cautious. It is not the virus that leads to interstitial lung disease and death. It is our immunological response, the “cytokine storm”, that causes severe illness.
This is comparable to the devastation of the respiratory syncytial virus, persistently responsible for bronchiolitis in the very young, killing tens of thousands worldwide each year.
If the vaccine is both effective and safe, enough people will be immune, and transmission from them to the rest of us will be much diminished. Indeed, if enough people are immune — generally about 60% (“herd immunity”) — either through exposure or vaccination, transmission ceases.
The Council of the International Epidemiological Association, its affiliate bodies and members have viewed with concern the rapidly evolving situation with the novel Coronavirus (COVID-19) pandemic. Since the onset of the outbreak in December 2019, this disease has affected 162 countries and territories (as of 17/03/2020) with over 184,000 people affected and 7,000 deaths. With countries at various response stages of anticipation, early detection, containment, and mitigation, we commend the efforts of the WHO, various national governments, non-governmental organizations, health workers and advocates in addressing this health crisis.
If COVID-19 were allowed to spread unchecked, it would devastate Australian society. My modelling suggests that Australia could get as many as 400,000 to 600,000 infections a day at the peak – translating to about 150,000 to 200,000 symptomatic cases a day. There’s no way we can let the numbers get that high. It would be absolute carnage.