Infection Through “Fleeting Contact” With The Delta Variant Leads To Lockdowns Across Australia

Map of Australia covid outbreaks

Australia struggles to keep new cases of the Delta variant under control. Sydney and Darwin have both entered lockdown due an outbreak of the Delta variant. Melbourne has come out of lockdown and Queensland and Western Australia have just recorded


While many are celebrating declining cases rates in the U.S. due to vaccination, other parts of the world are telling a different story. We are no longer dealing with the original Covid-19 virus that first emerged from Wuhan. Instead, we are dealing with a far more deadly virus, better-termed Covid-21. We have not yet seen the worst of this virus as it continues to evolve and adapt to outsmart prior interventions.  The previously successful methods used to control the virus in some countries are no longer proving effective.

Despite keeping cases close to zero for almost a year, China now finds itself locking down multiple regions to curb ongoing outbreaks. Taiwan is now in a similar position, experiencing its first surge after holding a record for the world’s longest Covid-free streak.

More people have died from Covid this year worldwide than in all of 2020. The official global death toll stood at 1,813,188 at the end of 2020 and more than 2 million people have died as a result of Covid so far this year, according to WHO.

The increased transmissibility of the Delta variant is a dire concern. In Sydney, Australia, several people were infected in “fleeting” non-physical contact in a cafe and a shopping mall. CCTV footage revealed two people walking past each other while at a mall transmitting the virus. NSW Premier Gladys Berejiklian told reporters in Sydney that “We also need to recognize that this Delta variant… is actually a gold medallist when it comes to jumping from one person to another,”. As the cluster of cases grew to 110, Sydney has entered a two week lockdown to curb further spread of the highly infectious variant amongst a largely unvaccinated population. The city of Darwin has also entered a separate two-day lockdown after a handful of cases were linked to a Delta variant outbreak on a remote mine.

Queensland’s chief health officer, Dr Jeannette Young decided to close the state’s borders to people from Sydney hotspots, telling The Guardian, “with the Delta variant, we’re seeing very fleeting contact leading to transmission. At the start of this pandemic, I spoke about 15 minutes of close contact being a concern. Now it looks like it’s five to 10 seconds that’s a concern. The risk is so much higher now than it was only a year ago.”

Several individuals in Australia were also infected with the Kappa variant through lingering virus aerosol particles in the hallway of a quarantine hotel in May. Though the individuals had no direct contact with each other they opened the doors to their hotel rooms within 30 minutes of each other and tested positive for the same strain. The incident led to more than 300 potential sites of exposure and more than 17,000 people potentially exposed to the virus, resulting in the state of Victoria locking down. A similar event occurred earlier in April where two families quarantining in rooms next to one another were found to share the same viral sequence, after briefly opening their doors 30 minutes apart.

These instances of transmission through “fleeting non-physical contact” should serve as a warning to the US and the rest of the world. Compared to the Alpha variant, the Delta doubles the risk of a person being hospitalized. An analysis of genomic surveillance data released by the Centers for Disease Control shows that the Delta variant now accounts for 20.6% of America’s Covid cases, up from 9.5% in the previous two-week period. Given the low and fragmented level of genomic surveillance in the US, it’s likely that this percentage is even higher than what is being reported.

We are also hearing similar reports of the rapid transmission of the Delta variant around the world and have witnessed how the Delta variant contributed to the most devastating wave of infections in India so far. Ninety percent of newly-detected COVID-19 cases in Moscow are being identified as the Delta variant as the city reported its highest ever death toll. The share of COVID-19 infections identified as the Delta variant of the coronavirus has doubled in Germany. Africa is facing a  devastating resurgence with cases rising for five straight weeks since the beginning of May and a 21% increase this month. 14 African countries have reported cases of Delta variant.

In Australia, these cases that emerge from ‘fleeting’ exposure are controlled by vigilant testing, contact tracing, and isolating systems but we have no such protections in the U.S., and vaccination uptake is continuing to stall. As cities across the US are reopening and removing restrictions, we can’t let public health measures like contact tracing and continued testing fall by the wayside also. With only 45% of all Americans (of all ages) fully vaccinated, over half the country is vulnerable to this more lethal variant. Children under 12 are still currently not eligible for vaccination. In some states, only about a third of the population has been fully vaccinated.  Globally there are also discrepancies between the efficacy of vaccines in use against the variants.

The stalling of vaccination comes even after a slew of vaccine incentives including; lotteries, college scholarships, gift cards, and free beer. The Biden Administration has also offered tax credits to employers that provide paid time off for people to get immunized, erected mass-vaccination sites, sent funds to community health centers, and partnered with local organizations, celebrities, and volunteers to get shots in arms. However, the initiatives have not had the expected impact, with the Biden Administration conceding that they will fail to meet their desired goal of 70% of adults vaccinated by Independence Day. The case rate among the unvaccinated seems to still be hovering at around the same rate as it was in January, when we were seeing upwards of 200,000 new cases a day in the US, demonstrating that the variants are still a powerful force in the US. A recent Covid outbreak at a Florida government building killed two people and hospitalized several others who were unvaccinated.

With the rapid rate at which the virus is evolving and the persistence of vaccine hesitancy, it is clear that the “vaccine only” approach will not be the pathway that leads us out of the pandemic. Vaccine breakthrough cases will continue to occur and those with compromised immune systems such as cancer or transplant patients are also not able to experience the full benefits of vaccination. Instead, we should be focusing on a multimodal strategy that utilizes preventative drugs, treatments, mass testing accompanied by dramatically scaled-up genomic sequencing in conjunction with vaccines. Only then can we create the multiple layers of protection needed to outsmart this ever-evolving virus.

The recent investment of $3.2 billion by the Biden Administration, to support the development of antiviral pills, is a wise decision and a great start, yet we need more focus on long-term strategies beyond the vaccines, impressive as they are.


Originally published on Forbes on June 28, 2021
© William A. Haseltine, PhD. All Rights Reserved.