Nearly a week into the nation-wide lockdown, the Coromandel has yet to produce a positive test result, despite Case A spending a weekend there. Matthew Scott looks at how that could have happened.
Little did Case A know the country would later pore over records of his sojourn to the Coromandel.
He would have had no idea the rest of New Zealand would soon have an opinion about his decision to visit the same cafe three times, or his curious five-minute visit to a real estate office.
Had he known he would be under the microscope, maybe he wouldn’t have spent his Saturday night watching the game in a crowded pub.
But unfortunately, none of us can be sure of whether the virus is coursing through our bloodstream or hanging out in the nasal cavity, ready to be propelled through the air by sneeze or cough like so many tiny paratroopers.
Fortunately, it doesn’t look like that happened in the Star & Garter Hotel last Saturday night, as more than a week on, all tests have come back negative and wastewater testing has detected no virus.
“We haven’t had any positive cases in Coromandel,” Director-General of Health Dr Ashley Bloomfield told reporters on Monday afternoon. “That’s promising.”
University of Otago epidemiologist Michael Baker said there were elements of chance and good luck at play.
“Everything about this is good management and good luck,” he said. “Even if you can turn the risk all the way down, you still might have bad luck.”
In the case of Case A and his weekend down in the Coromandel, luck may have been on the country’s side.
Baker said people tend to become non-infectious 10 days after the onset of their symptoms. “You go through a definite peak in viral load,” he said. “His viral load may have dropped and he may not have been particularly infectious at this point.”
Other factors at play keeping Case A’s Covid to himself may have been not getting close enough to another person to pass it on.
“For infection to occur, you need to have three things happening,” Baker said. “A person who’s infectious at the time, vulnerable people in the environment, and an environment that supports transmission.”
So the Star & Garter may not have ticked all of those boxes.
But a drop-off in testing numbers in Thames-Coromandel District may have made it harder to accurately determine whether Covid had come to town.
Before the weekend, the region was being praised by Bloomfield for high rates of testing, with 600 people in the district going for a swab. Over the weekend, however, fewer than 150 people were tested.
“This probably means that everyone who was at one of the locations of interest in and around Coromandel Town and Colville has already had their initial test and is self-isolating as required,” said Thames-Coromandel mayor Sandra Goudie. “In the next day or so people who were in a location of interest will be due to have their second test - their day five test - so we’re hoping the test numbers ramp up again.”
Coromandel Town has three testing stations - two pop-ups and one in a family health clinic.
“Ashley Bloomfield has singled out the Coromandel Peninsula as having had a terrific response to both testing and vaccinations, so let’s keep it up,” said Goudie. ““However, some people in our communities may still need to be tested, so take the opportunity, don’t delay.”
Nick Wilson, also a University of Otago epidemiologist, agreed with Baker that the variables may have been just right to prevent transmission.
“There is a lot of variability in how individuals spread this pandemic virus,” he said. "It depends on the stage of their infection and how much the virus has multiplied in the body, and then many situational factors.”
These factors could include how loudly people are cheering on the test match, or how heavily gym-goers are breathing - as well as aspects of the location such as ventilation and how crowded it is.
Wilson also noted the first Covid variant has 80 percent of infected cases arising from around 10 percent of infected people.
“I have not seen an equivalent estimate for the Delta variant - but it is still likely to be this similar pattern,” Wilson said. “That is, a minority of the initial cases trigger a majority of the secondary cases.”
