Covid-19 isolation should be cut to seven days: advisory committee

The isolation period for Covid-19 patients with symptoms should be reduced from 10 days to seven, the ministerial advisory committee (MAC) has recommended.

However, everyone with symptoms should be required to wear a mask at all times — even at home — from day eight to day 10, the committee says.

Its recommendation to health minister Joe Phaahla is dated December 16, the same date it suggested quarantining be discontinued with immediate effect for contacts of cases of Covid-19.

An advisory signed by the co-chairs of the MAC, Prof Kholeka Mlisana and Prof Marian Jacobs, said the isolation period was a trade-off between its limited benefits and its costs, “rather than an effort to reduce the chances of onward transmission to zero for the small proportion of cases that are identified”.

Because testing identifies only a small minority of Covid-19 cases, “isolation serves little overall public health purpose”, it said.

“Furthermore, isolation is associated with both significant strain on staffing levels and costs to the individual and to the broader society.

“Asymptomatic cases should not isolate at all, as a positive test does not indicate when they were infected, and shedding of non-infectious virus fragments can be protracted. Individuals are most infectious close to the time of their symptom onset.”

The MAC recommended that no Covid-19 test should be performed before a symptomatic patient returns to work after the seven-day isolation period.

“Testing prior to return to work is not feasible, as tests may remain positive for much longer than the period in which the patient is infectious,” it said.

The advisory said when a symptomatic patient returns to work in a healthcare setting, an N95 mask should be worn from day eight to day 10, and contact with extremely high-risk individuals — such as severely immunocompromised patients — should be avoided.

“A healthcare worker with Covid-19 is very unlikely to spread the disease to his/her coworkers in an environment where there is uniform wearing of masks, especially N95 masks (or equivalent),” said the MAC.

“Furthermore, the viral load in vaccinated individuals drops more quickly than in unvaccinated individuals, presumably rendering them non-infectious even more rapidly.”

The committee recommended that isolation rules should apply equally to vaccinated and unvaccinated people, and to high-risk and low-risk individuals.

“For any symptomatic patient, return to work from day eight onwards must, as always, take into consideration the patient’s clinical status. Only those patients who are well enough to work should do so.”

In early 2020, SA implemented a 14-day isolation period for all confirmed Covid-19 cases. They were counted from the date of symptom onset in mild cases, from the date on which clinical stability was achieved in severe cases, and from date of a positive test in asymptomatic cases. The period was reduced to 10 days in mid-2020.

“Since then, the local Covid-19 situation has changed in various ways,” the MAC said. “The proportion of people with some immunity to Covid-19 (from infection and/or vaccination) has risen substantially (exceeding 60-80% in several serosurveys).

“We have learned more about the manner in which Covid-19 is spread (including the high proportion of asymptomatic and pre-symptomatic spread), and also now have to contend with variants of concern whose epidemiology differs from that of the ancestral strains of SARS-CoV-2.

“Crucially, it appears that efforts to eliminate and/or contain the virus are not likely to be successful. Therefore, it is critical that the utility of containment efforts like isolation is re-evaluated.”

The MAC said its new recommendations were based on the suggestions of a technical working group consisting of experts from the MAC, the National Institute for Communicable Diseases, the National Institute of Occupational Health and the fields of public health and infectious diseases.

The advisory said from a public health perspective, the usefulness of isolation depends on rapidly identifying people with Covid-19.

“Unfortunately, there is good evidence that the rate of case ascertainment in SA is low. Testing is heavily biased towards symptomatic cases, but only a small percentage of cases (perhaps 16%) are symptomatic.

“Furthermore, only a limited proportion of symptomatic cases access testing, and even when testing is performed, false negative results occur. Thus, only a small proportion of positive cases are identified.

“Even when cases are correctly identified and timeously isolated, the bulk of onward transmission has likely already occurred, owing to SARS-CoV-2’s high propensity for transmission around the time of symptom onset, including substantial pre-symptomatic transmission.”

Isolation also economic and social consequences, including “significantly depleting staffing levels at healthcare facilities and in other front-line or critical workers in and outside the healthcare sector, which can threaten the integrity of these institutions”.

At an individual level, extended periods of isolation could result in loss of income, employment and schooling.

“Vaccinated individuals typically have a shortened period of viral shedding following breakthrough infections compared to unvaccinated individuals; the difference appears to be 2-3 days shorter,” said the MAC.

“Furthermore, the infectivity ... may be lower in vaccinated vs unvaccinated individuals even at the same viral load.”

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