Omicron: Should We Shorten Self-Isolation Time?

A health worker inoculates a woman with a dose of the Pfizer COVID-19 coronavirus vaccine as people receive booster shots inside a stadium in Bangkok on 8 January, 2022. (AFP Photo)

Omicron’s arrival has once again changed the course of the pandemic. The increased transmissibility of the COVID-19 variant means record numbers of people are being infected across the globe, and with each infection comes a period of isolation for every individual and their close contacts.

Most countries have ended their furlough schemes, so despite staff members being off with COVID-19 they have had to remain open, often short staffed. Even worse, healthcare and other front-line workers are having to take time off, potentially resulting in delays to lifesaving treatments for their patients. 

The push for an uptake in boosters against the new variant has been met with less enthusiasm than in the past, with people suffering from vaccine fatigue and wondering whether there will be an end to the constant jabs. But boosters do help protect against serious illness, even if not necessarily against catching the virus.

Some argue that because Omicron seems “milder”, we should aim to relax rules around restrictions and isolation. This is being flippant about a virus that has the potential to cause multisystem symptoms that can persist over a long period of time.

Wherever you sit on this argument, Omicron has the potential to cause huge workforce issues, something that has been recognised by the governments of the United States (US) and United Kingdom (UK), both of whom have slashed self-isolation times for those who test positive.

US health officials halved the recommended isolation time for people with asymptomatic COVID-19 from 10 to five days, amid a surge in cases, with the Centers for Disease Control and Prevention (CDC) updating its guidance on 27 December, 2021. 

The CDC recommends wearing a mask when around other people for the following five days. But experts have criticised the US’s lack of testing requirements to end isolation, arguing that letting people out early when they still have the potential to be infectious will only serve to infect more people. It is particularly worrying for those working with vulnerable people who they risk infecting if their own infection hasn’t completely cleared.

The UK also changed its self-isolation rules in December, reducing the required isolation timeframe from 10 to seven days, provided people have a negative lateral flow test on days six and seven – with tests taken 24 hours apart. As cases rise in the UK and we see record staffing shortages across multiple industries, there is pressure on the government to cut isolation further or to move away from PCR testing in those who test positive on a lateral flow test but have no symptoms – both of which could prove dangerous.

While some countries are changing their advice around isolation time, the World Health Organization (WHO) has not. It says people who test positive for COVID should isolate for 14 days. Countries like Germany and Jordan are following this advice, while France and Japan have a 10-day isolation period in place.

So, Who Is Right? 

Are these policy changes based on the science of protecting people against catching COVID, or are they governed by the economic impact that staff absences will have on businesses?

The answer lies in knowing how long people are infectious for after they catch COVID.

A major study published in JAMA Internal Medicine last year found people infected with the virus were most infectious two days before and three days after they develop symptoms. The CDC referred to this time period of infectiousness in its press release when they reduced the isolation time.

But this data refers to some, not all, people – and what we know about COVID is that it is unpredictable.

It makes sense that some of those who leave quarantine at five days are more likely to spread the virus, compared with those who are let out after 10 days. The decision to reduce isolation time, then, is clearly a trade-off in risk management and minimising disruption to the economy and wider society. 

It is a gamble, and the fact that the CDC is not recommending negative lateral flow tests before ending isolation has met strong criticism from many scientists. Although lateral flow tests are not perfect, needing a negative test result to release people from isolation early does seem prudent, especially with a new highly infectious variant like Omicron.

The UK’s approach to reducing isolation time to seven days does increase the risk of transmission by newly released individuals. However, its decision to utilise negative lateral flow tests to release those in quarantine seems more sensible than the US approach and will help mitigate the risks.

Analysis by the UK Health Security Agency (UKHSA) suggests that a seven-day isolation period together with two negative lateral flow test results has nearly the same protective effect as a 10-day isolation period without lateral flow testing for people with COVID-19. But the key word here is “nearly”, which suggests the protective effect they refer to is lower but balanced against the economic need, it is a risk worth taking.

Lateral flow tests, although imperfect, are good at picking up the most infectious individuals. A Cochrane review of 64 studies found that the tests correctly identify on average 72 percent of people who are infected with the virus and have symptoms and 78 percent within the first week of becoming ill. But in people with no symptoms, that drops to 58 percent. 

Clearly, this is a worry, as those who are allowed to leave isolation are those without symptoms and, according to this review, only 58 percent of those who have the virus will test positive and have to isolate further, while others will be free to roam around.

Of course, cautionary advice is given to those who are newly released: wear masks, social distance, and avoid indoor crowded spaces where possible. But not everyone will adhere to these rules.

The other fly in the ointment is the reduced vaccine efficacy and risk of re-infection with Omicron in those who have had infections from previous variants. We are letting people out early, a small proportion of whom might still be infectious with a virus that can infect the vaccinated or those who have had previous exposure – so the cycle is doomed to repeat itself.

All these decisions come down to balancing health and the economy. The irony, of course, is you cannot have a healthy economy without a healthy workforce so the two are inextricably linked. It remains to be seen what these decisions will mean for the workforce, hospitalisations and the general wellbeing of the population, but if there is one thing this pandemic has taught us is those countries that have erred on the side of caution during the pandemic have done better in terms of health and economy.