South Australia’s major health body warns the current risk of local transmission of serious and potentially deadly mosquito-borne diseases in the state is at its highest level since 2010.
SA Health said the 2010/11 season was the last time notified cases of the potentially deadly Murray Valley Encephalitis virus in humans was recorded in South Australia, with the most recent date before then being in 1974.
High numbers of the endemic Ross River virus were also detected in SA residents that year and the Government organisation said this season’s conditions are shaping up to be similar, particularly along the Murray River system.
Manager of health protection programs, Andrew Vickers, said the Bureau of Meteorology’s climate outlook shows moderate to strong La Nina conditions will remain until at least February.
“[The current forecast is] a little bit weaker than those conditions in 2010,” he said.
“This season we need to give people information on how they can protect themselves from getting bitten [because] there are no vaccines or cures for the viruses we get through mosquitoes in SA.
Mosquito threat likely to hang around
Mr Vickers explained the state’s mosquito control plan is guided by a hierarchy of responses based on triggers like climate forecasts and data from surveillance programs.
Level one is a standard risk, level two means there’s a medium risk to South Australians and level three is a high risk of arboviruses being transmitted to humans.
SA’s current season already started at level two in September because of the weather predictions and discovery of Murray Valley Encephalitis and the Kunjin virus in a flock of sentinel chickens at Ramco in the Riverland earlier this year.
Mr Vickers said there was potential for it to be upgraded to level three if a human contracted a mosquito-borne disease.
“Even if we detect those viruses in a chicken or a mosquito we trap, that wouldn’t push us to a level three,” he said.
“It would give us a heightened level two and ramp up our activity but level three requires human cases and that is possible.”
Communities encouraged to fight the bite
SA Health is working to support river councils with their mosquito monitoring, but said public awareness of mosquito control methods is the first line of defence.
Mr Vickers explained the annual ‘fight the bite’ education program which is about to commence has been allocated more funding this season.
“So preventing breeding of mosquitoes locally, wearing the appropriate clothes, avoiding going into mosquito-prone areas at dawn and dusk and using the repellents that are known to work.
“Mosquito bites are more than a nuisance, they can give you diseases and those diseases can be nasty and prolonged or potentially fatal.”
PARTISANSHIP HAS long coloured American perceptions of covid-19. Even so, the contrast between the top echelons of the main parties was striking on November 9th, the day the country passed 10m recorded cases of the disease. On that day the White House of outgoing President Donald Trump was dealing with reports that it may have hosted a second superspreading event in the span of a month—this one for an election-night party that may have sickened Ben Carson, the housing secretary, among others. The same day, President-elect Joe Biden announced the members of the coronavirus advisory board for his transition, staffed by the sort of public-health experts the president likes to mock.
While national attention was otherwise diverted, an extraordinary third surge in covid-19 infections began in the weeks before the presidential election. There are now 1,000 new deaths reported each day along with 120,000 new infections. Even though testing has been ramped up to nearly 1.5m per day, the test-positivity rate is approaching 10%—suggesting that even now, many infections are being missed. In all but a handful of states, there seems to be uncontrolled transmission, limiting the efficacy of contact-tracing. Hospitalisations had been declining up until the end of September, when they bottomed out under 30,000. Now they have doubled to over 60,000—higher than the previous peak in April. In North Dakota, the location of the worst outbreak in the country, nearly every intensive-care bed is occupied.
The argument that Mr Trump has handled the epidemic uniquely terribly may just have cost him the election. However, this most recent surge is not an America First phenomenon. It has roughly coincided with a second wave in Europe which, measured both by deaths and by cases per person, is even more severe. European countries have reimposed harsh lockdown measures, whereas the president and America’s governors have been less draconian. France’s intensive-care wards look almost as strained as those of North Dakota. But whereas President Emmanuel Macron has declared a second national lockdown, Governor Doug Burgum, a Republican, recently declined to impose even a mask mandate in his state.
Forecasting the course of the disease has proved supremely difficult. It is therefore unclear how bad a situation a newly inaugurated President Biden would inherit on January 20th 2021. But current signs do not augur well. Ashish Jha, dean of the Brown University School of Public Health, reckons that there may be 100,000 new deaths between now and then. The Economist’s best estimate of total deaths in America, including those we think are missed by official reporting, is nearly 300,000. After nine long months of living with the virus, Americans and their elected officials seem tired of restrictions on movement and businesses. With no new curbs, exponential growth could continue for weeks. Cold weather may push more people to move their gatherings indoors, where transmission is much more likely. Many Americans will travel for Thanksgiving and Christmas; no politicians will want to take the blame for cancelling the holidays.
Federal action on the economy does not seem imminent either. Democrats and Republicans in Congress have been deadlocked over a new economic stimulus since many supports expired in July. The stalemate has not yet been broken. Nancy Pelosi, the Democratic leader in the House of Representatives, may wish to hold out for the larger package her party could achieve if Democrats win two run-off Senate elections in Georgia, thus flipping control of the chamber. Mitch McConnell, the Republican leader in the Senate, may not want to concede a pre-emptive victory to the Biden administration.
A virus spreading fast with no compensating stimulus would be a brutal starting position for a Biden administration. Even with expedited approval and distribution, getting a vaccine to every American who needs it would take months (see Briefing). Mr Biden has announced plans to take more serious federal action. He has named Ron Klain, who co-ordinated Obama White House’s response to an Ebola outbreak in 2014, as chief-of-staff. Mr Biden would use his executive authority to create a Rooseveltian Pandemic Testing Board to compel companies to produce more tests, laboratory materials and personal protective equipment. He probably lacks the authority to impose a mask mandate nationwide, but would push states to do so.
Most Republican governors are already wary about implementing public-health measures. They might see the chance to defy Mr Biden’s recommendations as an additional incentive to stay that course. Democratic ones seem averse to a European-style response too. The ban announced by Phil Murphy, the Democratic governor of New Jersey, on indoor dining in restaurants between 10pm and 5am, typifies the urge to do something, but not too much.
In her vice-presidential debate with Mike Pence, Kamala Harris expressed some distrust in the imminent vaccine Mr Trump had been hyping ahead of the election. “If the doctors tell us we should take it, I’ll be the first in line to take it. Absolutely. But if Donald Trump tells us to take it, I’m not taking it,” she said. Republican voters offered a new vaccine by President Biden might be similarly sceptical. Already, 33% of Republicans tell pollsters that they would not take a coronavirus vaccine when it becomes available, compared with 18% of Democrats and 31% of independents.
While campaigning, Mr Trump liked to talk about covid-19 as though it were almost over. “It is disappearing” he said on October 10th, shortly after contracting it himself. “We are rounding the corner,” he argued on October 22nd. The assessment of Mr Biden’s transition team is more in tune with reality, which is a good start. “Our country is facing an unprecedented time with covid-19 cases accelerating nationwide,” says Marcella Nunez-Smith, a Yale epidemiologist who is co-chairing Mr Biden’s advisory board. Anyone who hopes the virus will go away once America installs a president who follows scientific advice is likely to be disappointed.■
Editor’s note: Some of our covid-19 coverage is free for readers of The Economist Today, our daily newsletter. For more stories and our pandemic tracker, see our coronavirus hub. For analysis of the presidential transition, explore our US elections hub
This article appeared in the United States section of the print edition under the headline “Transmission and the transition”
Federal Trade Minister Simon Birmingham has not yet heard from his Chinese counterpart, despite the Federal Government signing the largest ever free trade deal in history.
The Regional Comprehensive Economic Partnership (RCEP) was signed yesterday, with 15 countries including Australia, China, Japan, South Korea, New Zealand and the 10 members of the Association of South-East Asian Nations (ASEAN) including Indonesia and Vietnam, agreeing to the deal.
Mr Birmingham told Today he was yet to hear from Beijing, as tensions between Australia and China continue to loom.
“Our position remains the same,” he said.
“We do want to see these types of regulatory disruptions stop.
“They’re deeply troubling and they’re causing pain to Australia.”
Canada’s chief public health officer said today there’s little evidence — if any — of COVID-19 transmission among passengers travelling by air.
Speaking to reporters at a COVID-19 briefing, Dr. Theresa Tam said that while the Public Health Agency of Canada (PHAC) is aware of reports that some COVID-19-infected people have travelled to Canada by air, there have been few documented cases of the virus actually being passed to others travelling on those same flights.
“There have been very few reports, extremely rare reports, actually, of transmission aboard aircraft,” Tam said. “Very, very little.”
In fact, Tam said she’s not aware of any in-flight transmission being reported to provincial public health authorities. “We have not received that kind of report,” she said, adding officials should relay that sort of information to her agency if they have it.
Tam said the negligible number of cases reported from flying is likely attributable to the strict cleaning measures that airlines have implemented since the onset of the pandemic.
For example, Air Canada — the country’s largest carrier — passes cabin air through High Efficiency Particular Air (HEPA) filters about 20 to 30 times per hour during flights. The result is a mix of filtered air and fresh air from the outside.
The filters are similar to those used in hospital operating rooms and, according to Air Canada, are extremely effective at trapping microscopic particles as small as viruses and bacteria, along with dust, pollen and moisture.
WestJet also uses a HEPA filter system and says it “captures and filters 99.99 per cent of all airborne particles so you can breathe a little easier.”
The Calgary-based airline also has implemented a cleaning process called “fogging,” which sees the entire aircraft interior regularly disinfected with a hydrogen peroxide-based cleaner.
“I think we are learning more and more about some of the technologies, if you like, in terms of the ventilation and the way that the aircraft ventilation works. The modern aircraft is actually really good in terms of air exchanges and the way airflow occurs in the cabin,” Tam said.
Tam said these ventilation systems — together with mandatory mask policies and instructions to passengers to keep to their seats and face forward while in flight — have made planes comparatively safe places to be during this pandemic.
Tam pointed out, however, that the in-flight experience is just one aspect of air travel. She said passengers can still be exposed to COVID-19 while travelling to and from the airport or waiting in an airport lounge.
She said that, for now, Canada will maintain its mandatory 14-day quarantine period for returning foreign travellers to reduce the potential for community spread. The airline industry has been ravaged by government-imposed travel restrictions and quarantines; Air Canada alone has reported hundreds of millions of dollars in losses.
Tam said the government is monitoring a PHAC-sponsored pilot project in Alberta that allows returning travellers to take a series of tests rather than isolate for two weeks. Ontario Premier Doug Ford has said he’d like to see a similar program in place in the country’s largest province.
Safer than shopping?
Tam’s comments follow reports out of the U.S. that also found the rate of in-flight COVID-19 transmission is minimal.
Researchers at the university’s T.H. Chan School of Public Health found that even though air is recirculated back into the cabin during a flight, the high-quality filters used on most commercial airliners mean virus droplets from one passenger are unlikely to infect another.
The “layered approach, with ventilation gate-to-gate, reduces the risk of SARS-CoV-2 transmission onboard aircraft below that of other routine activities during the pandemic, such as grocery shopping or eating out,” the study said.
The ventilation system isn’t enough on its own, however. Harvard’s researchers said masks, frequent cabin cleaning and a robust screening system for symptomatic passengers also play critical roles in keeping travellers healthy.
In fact, the study concluded that the use of face masks is “the most essential part of a comprehensive set of measures to reduce COVID-19 during air travel.”
The study was sponsored by a major U.S. airline lobbying group, Airlines for America, but Harvard researchers said their findings and recommendations are “independent conclusions.”
Through a simulation study of airflow onboard a United Airlines Boeing 777 aircraft, the military researchers found that about 99.99 per cent of particles were filtered out of the cabin within six minutes due to fast air circulation, downward air ventilation and aircraft filtration systems.
It estimated that, in order to receive an infectious dose, a passenger would need to fly 54 hours on a plane with an infected person.
The research was conducted over six months and involved 300 tests during 38 hours of flight time and 45 hours of ground testing.
The tests were done by releasing particles the same size as the novel coronavirus across the entire cabin by section. Each section had 42 sensors representing passengers.
A group of researchers from across the United States working in collaboration with their Swiss counterparts have conducted an extensive population-based serological survey to understand the transmission dynamics of severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) – the novel agent that causes coronavirus disease 2019 (COVID-19).
Their study titled, “Household Transmission of SARS-COV-2: Insights from a Population-based Serological Survey,” is available on the preprint server site medRxiv.*
The background and need for the study
With a high transmission rate between persons, over 50 million individuals have been infected with SARS CoV-2 around the world since it first emerged in Wuhan, China, in late December 2019.
Those in household contact with an infected person are thus at a greater risk of acquiring the virus. Studies looking at the transmission of the virus within household contacts are thus vital in better understanding COVID-19’s transmission.
At present, studies looking at the household transmission of COVID-19 depend on detecting contact-based infections by using reverse transcription-polymerase chain reaction tests (RT-PCR), a nuclear-derived method that can detect the presence of SARS-CoV-2’s genetic material in host cells. This is currently the most common form of testing and is usually conducted using nasal swab samples. Currently, those who have been in contact with individuals exhibiting mild symptoms or no symptoms may be missed in RT-PCR testing due to the limited time window in which virological testing may yield positive results. The study’s authors explain that these limitations may underestimate the actual mild or asymptomatic cases among the household contacts and miscalculate the household secondary attack rates.
Serological surveys search for the presence of antibodies against SARS-CoV-2 in a person’s blood. The researchers suggest that this form of testing could be an effective alternative way to detect the virus’s spread among household contacts. For one, these serological surveys yield positive results for an infected person for a longer duration compared to the RT-PCR test.
A recent large meta-analysis of other studies has shown that the household secondary attack rate is around 17 percent. Studies have thus missed several aspects in estimating household infection rates and so to help fill the knowledge gaps. This study was undertaken using serological surveys.
Frequency of households of different sizes in the study (A), proportion seropositive by house size (B) and distribution of the number of seropositive people in household by size (C).
Importance of this study
This study was undertaken to clarify the transmissibility of asymptomatic infections as well as infections from household and community contacts among patients with COVID-19. This would help understand and design ways to control the spread of the infection, wrote the researchers. Serological studies helped detect all previously infected individuals, the team wrote.
This was the SEROCoV-POP study, which is a population-based study of individuals aged between 20 and 74 years from Geneva (Canton), Switzerland.
All the participants in the survey (10,587 in total) were invited to take part in the serological survey. Participants were asked to bring all the members in their household aged over 5 years. Within household and external household contacts were taken into account since January 2020.
All the participants of the study and household contacts were asked about any symptoms they may have, including cough, fever, shortness of breath, or loss of smell or taste since January 2020 up till 2 weeks prior to the serological blood test. For all the participants, anti-SARS-CoV-2 IgG antibodies were detected using enzyme-linked immunosorbent assay (ELISA) tests. The antibodies were against the S1 domain of the spike protein of SARS-CoV-2.
The team utilized chain-binomial models to assess the number of infections spread within the households and estimated the risk of transmission within the household and extra-household contacts.
For this study, a total of 4,524 household members 5 years and older participated from 2,267 households between April and June 2020. The median age was 53 years, and 53.6 percent of the participants were female. Overall results were:
The risk of infection from a single infected household contact was 17.2 percent (95% CrI 13.6-21.5 percent)
The risk of infection from an extra-household contact was 5.1 percent (95% CrI 4.5-5.8 percent)
With increasing age, the risk of getting infected from a household contact rose from 7.5 percent (95% CrI 1.3-20.3 percent) among children aged between 5 and 9 years to 30.2 percent (95% CrI 14.3-48.2 percent) among those over the age of 65 years.
The risk of infection from an extra-household contact was greatest among the working-age group of individuals aged between 20 and 49 years.
Household contacts who were positive for antibodies but did not have symptoms of COVID-19 had a 74.8 percent lower odds (95% CrI 43.8-90.3 percent) of infecting another household member when compared to a positive contact who had symptoms (19.6 percent 95% CrI 12.9-24.5 percent).
Conclusions and implications
This study shows that the risk of getting infected with SARS CoV-2 after exposure to a single infected household member was four-times greater than from an external positive contact. The team noted that younger children were at a lower risk of getting infected from household contacts compared to the elderly and asymptomatic cases are less likely to spread the infection among contacts within the household. The authors wrote, “While the small households in Geneva limit the contribution of household spread, household transmission likely plays a greater role in other settings.”
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.
“But more importantly, to give all Victorians, the reassurance that when we do start down this path, we start down this path with absolute assurance that we’ll stay safe and stay open. He would not say whether his department should be the lead agency for a future hotel quarantine program.
“We want to make sure that we give a comprehensive response to all of the recommendations, not pick a few out, because they’re all interrelated and intertwined.”
Mr Foley said testing in Victoria had increased in recent weeks, but more would be done to ensure it is broad enough to catch any outbreak early.
“Victoria over the past month has actually increased testing levels as numbers have come down more broadly. We’re running 30 per cent above New South Wales, in actual figures, let alone per head of population,” he said.
“There’s more we can do, whether it’s in innovation testing around workplaces, targeted communities. And now as we open up, particularly in the regions.”
Asked whether he could say yet how many patients had contracted the virus in Victorian hospitals, Mr Foley said that figure was yet to be determined.
“When you’ve got some 20,000 cases in Victoria, over 3000 health care workers, with complex settings, it actually does take some time to go through when it comes down to genomic testing and sequencing. And if we’re going to learn from the past, we need to make sure that we have all the evidence, based on the science, accountably and transparently released. And as soon as that complex work is finished, we’ll certainly be releasing it.”
More than 1.25 million people have died from the respiratory disease that emerged in China late last year.
The pandemic’s recent acceleration has been ferocious. It took 32 days for the number of cases to rise from 30 million to 40 million. It took just 21 days to add another 10 million.
Europe, with about 12 million cases, is the worst-affected region, overtaking Latin America. Europe accounts for 24% of COVID-19 deaths.
The region is logging about 1 million new infections every three days or so, according to a Reuters analysis. That is 51% of the global total.
France is recording 54,440 cases a day on the latest seven-day average, a higher rate than India with a far bigger population.
The global second wave is testing healthcare systems across Europe, prompting Germany, France and Britain to order many citizens back to their homes again.
Denmark, which imposed a new lockdown on its population in several northern areas, ordered the culling of its 17 million minks after a mutation of the coronavirus found in the animals spread to humans.
The United States, with about 20% of global cases, is facing its worst surge, recording more than 100,000 daily coronavirus cases on the latest seven-day average, Reuters data showed. It reported a record of more than 130,000 cases on Saturday.
The latest U.S. surge coincided with the last month of election campaigning in which President Donald Trump minimised the severity of the pandemic and his successful challenger, Joe Biden, urged a more science-based approach.
Trump’s rallies, some open-air and with few masks and little social distancing, led to 30,000 additional confirmed cases and likely led to more than 700 deaths, Stanford University economists estimated in a research paper.
In Asia, India has the world’s second-highest caseload but has seen a steady slowdown since September, despite the start of the Hindu festival season. Total cases exceeded 8.5 million cases on Friday and the daily average is 46,200, according to Reuters data.
The government’s chief scientific adviser says he is “not aware” of any cases of Covid-19 transmission between children playing football outdoors.
Youth sport will only be permitted in schools.
Sir Patrick Vallance said the measures also take into account “interactions” at events such as grassroots sport outside school.
England’s chief medical officer Professor Chris Whitty and Vallance were asked about the suspension of youth sport in a science and technology select committee meeting on Tuesday.
When asked by chairman Greg Clark MP if he knew of any instance of coronavirus infection taking place between children playing grassroots football, Vallance said: “Not that I’m aware of. There may be evidence, but I haven’t seen it.”
Clark said the ban on youth sport seemed “perverse” given the low transmission rates outdoors and the importance of exercise for children and asked whether it was something Vallance could “further advise” the government on.
“We’ve been very clear as to where we think the areas of transmission are most likely to be,” said Vallance.
“But we must also be very clear that an entire package must take into account everything, including interactions around events, which become quite important.
“Then it’s for policy makers to decide what policies they want to adopt on the basis of that.”
When asked by Clark if they advised the government that outdoors children’s sport should be banned, Vallance said: “They’ve had advice from us in terms of the general principles but not down to specific individual activities like that.”
Whitty added it would be “deeply unhelpful” for them to start “trying to unpick really difficult packages” that the government had put together by advising them to reverse a ban on children’s grassroots sport.
He said: “This is a difficult balancing act across government. We fully understand that and our job is to give the broad advice and then leave it up to them to integrate the various elements.”
Elite sport can continue behind closed doors during the lockdown.
There were calls for youth sport to be exempt when the new restrictions come into effect on Thursday.
Former Wales midfielder Robbie Savage, who coaches a junior team, criticised the decision to suspend children’s sport in a series of tweets, asking Culture Secretary Oliver Dowden if he realises “the impact of this decision on youngsters’ mental and physical wellbeing?”
“Obviously in the context of very strong restrictions people aren’t having contact with many people, but we think that puts us in an extremely good position to use the app going forward,” she said.
The app was developed as part of the government’s COVIDSafe strategy, which included advertising for social distancing and good hygiene practices.
Opposition health spokesman Chris Bowen said Labor was supportive of any tool to ease the burden of the pandemic.
But given Australia has recorded 27,520 cases of COVID-19 and uncovered hundreds of thousands of close contacts the app was clearly ineffective.
“This app has been a huge bungle,” he said.
Senate estimates also heard on Monday that the level of mental distress has increased across Australia but soared in Victoria as the pandemic has worn on.
Outside Victoria and NSW, use of Kids Helpline increased 18 per cent, Beyond Blue use rose 8 per cent, and Lifeline calls increased by 18 per cent, senate estimates heard.
But in Victoria alone, Kids Helpline services rose by 61 per cent, Beyond Blue help went up by 67 per cent and Lifeline calls rose by 40 per cent.
Use of medicare mental health services in Victoria in the four weeks to October 11 was also 31 per cent higher than the equivalent four-week period a year earlier, first assistant secretary for the Department of Health Mark Roddam said.
Liberal Senator Dean Smith asked Mr Roddam if that showed the pandemic had affected Victorians more than the rest of the country.
“Clearly Victorians are reaching out for support in a much larger proportion than the rest of the country,” Mr Roddam said on Monday.
Senator Smith whether demand for mental health services was continuing to increase or whether it had peaked, Mr Roddam said he expected those numbers were coming back down.
“I would think senator based on what we saw in the rest of the country from May onwards that we would start to see those numbers come back now, as the pandemic in Victoria comes under control,” he said.