Big difference in Covid-19 random tests in NZ and US

Street testing has been carried out in various parts of New Zealand and is not finding positive Covid-19 cases, which suggests the community spread of the virus is very low (although some claim we still insufficient data to make decisions about reducing lockdown restrictions).

All (about 340) tests processed  from the Queenstown supermarket site returned a negative result.

All 308 tests done in the Waikato (Otorohanga, Hamilton, Matamata, Cambridge, and Te Awamutu) were also negative.

All test results to date done in Christchurch are also negative. Testing groups of the public is continuing, now in Auckland.

In contrast in the US One third of participants in Massachusetts study tested positive for antibodies linked to coronavirus

Around a third of participants in a Massachusetts study tested positive for antibodies linked with coronavirus, according to researchers.

The Mass. General study took samples from 200 residents on the street in Chelsea, MA. Participants remained anonymous and provided a drop of blood to researchers, who were able to produce a result in ten minutes with a rapid test.

Sixty-four of the participants tested positive – a “sobering” result, according to Thomas Ambrosino, Chelsea’s city manager.

“We’ve long thought that the reported numbers are vastly under-counting what the actual infection is,” Ambrosino told the Boston Globe. “Those reported numbers are based on positive COVID-19 tests, and we’re all aware that a very, very small percentage of people in Chelsea and everywhere are getting COVID-19 tests.”


Ambrosino called Chelsea the epicenter of the crisis in Massachusetts. Chelsea has the state’s highest rate of confirmed cases, with at least 712 confirmed cases and 39 deaths – an infection rate of around 2 percent.

Even so, that positive rate must be a concern.

The daily rate of new cases in the US has flattened off but is still running at about 30,000, with a total recorded cases of 728,293.

The death rate has more or less flattened to, but is running at over 2,000 deaths per day (yesterday 2,535), with the total 37,154 which is well above any other country, with Italy on 23,227 and Spain 20,043.

There has only been half as much testing or less in the US than Italy, Spain, Germany, Switzerland, Portugal, Austria, Norway, Israel and South Korea.

The testing rate in New Zealand is a bit behind the biggest testers but is still 50% higher than the US.

New Zealand locked down quicker and more comprehensively than most countries (from 22 to 26 March) and so far has benefited from that.

Our daily increase in cases rose steeply to 70 on 26 March and peaked at 89 on both 2 and 5 April, but has dropped off quickly since then (the last three days have been 15, 8 and 13), even though more testing has been done.

Total confirmed and probable cases over time

So for now Covid-19 looks contained here, but there is now debate and big decisions to be made about how soon and home much to relax lockdown restrictions. Government will decide on Monday whether to drop from Level 4 to Level 3 on Thursday or not.

Some are saying things like Data isn’t enough for this decision, and there are doubts whether the New Zealand goal of eliminating the virus from the country can be achieved. Virologist on latest Covid-19 science:

It will be very difficult to eliminate Covid-19 completely from circulation in New Zealand when so many cases are believed to be asymptomatic, a leading UK virologist says.

Dr Chris Smith, consultant clinical virologist at Cambridge University and one of BBC Radio 5 Live’s Naked Scientists, says he’s been talking to lots of virologists and vaccine experts in the last few weeks and they are very sceptical.

“Most people are of the opinion, given how well optimised this new coronavirus is, it has a really high prospect of becoming another circulating coronavirus and causing seasonal infections and cold-like symptoms or in rare cases more severe outbreaks, because by the time that presumably happens the vast majority of us will have become immune to it either because a vaccine has been invented or because we’ve become naturally infected with it.”

But he believes it will take an extended time before a vaccine is ready and in the meantime many countries won’t be able to sustain lockdown measures, and the disease will resurge as a result.

However the random tests so far suggest there may be few asymptomatic undetected cases in New Zealand.

It doesn’t look so good in the US – A New Statistic Reveals Why America’s COVID-19 Numbers Are Flat

According to the Tracking Project’s figures, nearly one in five people who get tested for the coronavirus in the United States is found to have it. In other words, the country has what is called a “test-positivity rate” of nearly 20 percent.

That is “very high,” Jason Andrews, an infectious-disease professor at Stanford, told us. Such a high test-positivity rate almost certainly means that the U.S. is not testing everyone who has been infected with the pathogen, because it implies that doctors are testing only people with a very high probability of having the infection.

…The test-positivity rate, then, is a decent (if unusual) proxy for the severity of an outbreak in an area. And it shows clearly that the U.S. still lags far behind other countries in the course of fighting its outbreak.

Comparing American states to regions in other countries results in the same general pattern. In Lombardy, the hardest hit part of Italy, the positive rate today stands at about 28 percent. That’s comparable to the rate in Connecticut. But New York, so far the hardest hit state in the U.S., has an even higher rate of 41 percent. And in New Jersey, an astounding one in two people tested for the virus are found to have it.

Five other states have a positive rate above 20 percent: Michigan, Georgia, Massachusetts, Illinois, and Colorado.

In New Zealand difficult decisions need to be made about keeping our Covid-19 infection rate right down, but the US is still battling high infection and death rates and appears to have widespread community infection in some areas.