The Government should be careful about banning people entering New Zealand from specific countries based on the presence of variants of the virus that causes COVID-19, given most countries are not testing for variants, University of Otago experts say.In an opinion article published today by Newsroom, McAuley Professor of International Health, Philip Hill, and Associate Professor of Epidemiology Brian Cox, highlight the fact that the vast majority of countries, including the USA, do little or no sequencing of the virus.
“We should be careful about banning people entering NZ from specific countries based on the presence of the UK or other known variants, given there is so little sequencing being done in other parts of the world.
“We just don't know enough about the global distribution of variants to treat people from some countries as more or less safe to come to NZ on that basis,” the Professors say.
They have carefully reviewed data from the UK and say it does point to a real increase in transmissibility of at least one variant of the virus that causes COVID-19. While it is not entirely clear how much, they claim somewhere between a 10 and 70 per cent increase seems likely.
It is important to note that phenomena like this are commonly observed in infectious diseases, they say. For example, their work in tuberculosis (TB) has shown the Mycobacterium africanum strain of Mycobacterium tuberculosis is just as likely to transmit, but is a lot less likely to cause TB disease than other strains.
There are a number of reasons to be cautious about the findings from the UK, they say. Firstly, the UK only sequences the virus from less than 10 per cent of all COVID-19 cases. While this is still a large number of cases to analyse, it would be expected to see at least 50 per cent of cases sequenced when doing in-depth analyses linking sequencing data with epidemiological data, to ensure the data is accurate.Secondly, the vast majority of countries, including the USA, do little or no sequencing of the virus. “Therefore, rather than singling out the UK and South Africa as having variant strains of concern, we should interpret the finding from the UK as demonstrating that strain variation in transmission occurs for this pathogen and there are almost certainly more variants that have the same ability around the world, but remain unidentified.
“We do not actually know where this variant originated from – it could well have been imported into the UK, rather than have evolved there. Therefore, we need to be suspicious of any strain from anywhere.”
Knowledge about the new variants will assist in New Zealand's approach to COVID-19, the experts say. “We should continue to strengthen our infection controls at the border and increase our capacity to respond to an outbreak using the full combined force of all tools now at our disposal. These things are already happening.”
Professors Hill and Cox recommend the New Zealand Government ensures that approval processes for new vaccines and national vaccine distribution planning are in place as quickly as possible, so they do not inhibit decision-making about when a vaccine programme can commence.
They also recommend being very careful to choose the “right” vaccine, so as not to precipitate conditions that promote the emergence of new virus variants.
“A vaccine that has relatively low protection against infection, and/or has relatively low protection against disease, should be avoided if a vaccine that protects better against infection and disease is available, even if it is more expensive.”
For further information, contact:
Professor Philip Hill
McAuley Professor of International Health
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