Second, data from South Africa shows the risk of hospitalisation with Omicron compared with Delta is reduced by 80 per cent and, once in hospital, the risk of severe diseases with Omicron is reduced by 70 per cent. Britain has now reported that although hospitalisations are increasing with Omicron, they don’t appear to be rising as fast as infections, and the proportion of people in hospital needing intensive care is vastly reduced with Omicron compared with Delta. These are all very encouraging data.
But Omicron is not simply a mild cold that we can dismiss. Hospitalisations from Omicron are occurring across the world and in Australia, and the impact of this variant on the unvaccinated (including children) and immunosuppressed is still not well understood. Omicron can still cause disease. Even though there is a smaller risk of hospitalisation, if we have very large numbers of infections then the pressure on our healthcare setting will rapidly accelerate.
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Although Delta has not gone away, Omicron now accounts for at least 50 per cent of infections in NSW and Victoria. Therefore, getting a booster, wearing masks in public indoor areas and getting tested when exposed or symptomatic remain critically important to slow spread of both variants.
The definition of close contacts is hopefully now uniform across the country (except for WA which remains essentially COVID-free) and only requires quarantine for household contacts who have had more than four hours contact with an infected person. Is this four-hour rule based on extensive research and evidence? No. Does this policy mean that casual contacts are no longer at risk? No. However, the risk of infection is vastly increased with the sort of prolonged and close exposure typically linked to a household contact. Therefore, this new policy will focus resources and efforts – such as quarantine for seven days – only on those at the highest risk of infection.
Casual contacts will get tested should they develop symptoms. This risk-stratified approach is commonly how difficult decisions get made in public health. This is how we run our entire health system daily: resources need to go where they will have the greatest impact.
Finally, what about the apparent shift in attitudes towards antigen tests? It might feel like Australia has done a complete about-face on them. We were first told they weren’t good enough compared with the “gold standard” PCR testing.
This was certainly the case when we were in elimination mode, and when our PCR system was not under such immense strain. But now that we are using a risk-stratified approach to live with COVID-19, antigen tests can and will play an important role.
Antigen tests are very good at detecting the people we need to find and isolate: those with high amounts of virus in their nose (who are therefore more infectious). But the Achilles heel of antigen tests is that they will miss people with lower amounts of virus.
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Based on recent published work from the Doherty Institute, we know that antigen tests work just as well with Omicron as with Delta. The great challenge now is how to ensure equitable and easy access to antigen tests. These tests must be free when used for decisions in relation to isolation and quarantine. We have to also ensure the tests are used optimally in vulnerable groups. Culturally appropriate education about their use and implementation research will be needed to ensure the tests are doing the job we want them to do.
Viruses are clever beasts. But as our toolbox continues to expand, we will outsmart COVID-19. Widespread vaccination both in Australia and globally, masks and other public health measures remain the cornerstone of our response.
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Strategic use of new testing modalities will need to be adapted and optimised. We need to use antibody infusions to protect the most vulnerable from hospitalisation while new therapeutics such as oral antivirals will almost certainly be available in Australia in coming months.
Our bumpy ride with COVID-19 will continue in 2022, but it will certainly get smoother over time.
Professor Sharon Lewin is director of the Doherty Institute. Her University of Melbourne colleague Professor Deborah Williamson is director of the Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital, at the Doherty Institute.
Why our big COVID switch is wise
Source: Philippines Alive
