What you need to know about 'active' and 'recovered' COVID-19 cases

CANBERRA — Globally the number of confirmed COVID-19 cases has passed 50 million, according to Johns Hopkins University’s Coronavirus Resource Center, with over 1.2 million deaths. But the data also shows that 65% of confirmed cases have recovered to date, with 32% remaining “active.”

In assessing the global situation, active and recovered cases appear to provide a more accurate picture to understand the current crisis. In India, reporting on the recovered cases — including 1 million recoveries within 13 days — enables the conversation to move beyond the alarming totals.

More than 8.5 million cases have been confirmed in the country, impacting 6 out of every 1,000 persons. But just 6% are active, according to official national statistics. Indonesia is also promoting recovered statistics as part of media engagement, highlighting “cumulative cures” that continue to increase daily.

The challenge of reporting on active and recovered cases becomes immediately evident while reviewing the COVID-19 dashboard created by the World Health Organization — active and recovered cases are missing from country and global reports.

“WHO is monitoring the pandemic at global level via the number of cases and information provided by [member states] themselves,” a WHO spokesperson told Devex. “The number of cases who recover after the disease is assessed differently in every country. [Member states] are using different and complementary information systems to monitor the epidemic and the data quality might have been assessed in [member states] for in-country use and is not systematically shared with WHO.”

Inconsistencies in methodologies exist in reporting these figures both between countries and even between jurisdictions within a country creating a challenge when reporting at the global level.

When is a patient considered recovered?

Tom Duszynski, director of epidemiology education with the Indiana University-Purdue University Indianapolis, explained in The Conversation that a patient is considered medically recovered from COVID-19 after antibodies fighting the infection have successfully contained the virus, preventing the virus from replicating and supporting recovery. When they have no long-term health effects or disabilities, they are considered recovered.

Defining that in data, Duszynski said, is more challenging. Some health agencies are more cautious than others in defining a recovered patient.

In May, when the U.S. state of Arizona sought to release information on recovered cases, officials faced challenges with no standard definitions of recovered — an ongoing challenge. The sheer numbers of cases also meant that automation was required to define this based on knowledge of the virus and its impact rather than medical tests confirming the patient had recovered.

In Alberta, Canada, Alberta Health has defined a recovered case as one where 14 days have passed between a confirmed case and no required hospitalization or additional treatment, 10 days since a hospital discharge, or two negative tests at least 24 hours apart.

In Australia, definitions between internal jurisdictions can differ. “States and territories are providing the Department of Health with a daily figure on the number of cases that they have assessed as having ‘recovered’ from their COVID-19 infection,” a spokesperson for the Australian Department of Health informed Devex.

“The approach taken by jurisdictions in ascertaining or basing a case’s recovery varies by jurisdiction, but aims to reflect the criteria for release from isolation as described in the CDNA [Communicable Diseases Network Australia] public health guidance for COVID-19.”

But high-income countries are more likely to make their definitions available. In low- and middle-income countries, including Papua New Guinea, statistics on COVID-19 recoveries may be published but there is no publicly available information on how it is defined and tests required to confirm recovery.

Where active cases are highest, recovery is not reported

Creating an even bigger challenge is the reporting of active cases where there is no, or questionable recovery data. According to Johns Hopkins data on Dec. 21, a total of 13 countries had active cases accounting for more than 75% of their confirmed total. In Serbia, 99% of confirmed COVID-19 cases were active. In Sweden active cases sat at 98%, 97% for Belgium and 96% in the United Kingdom.

But in Serbia, the Netherlands, Belgium, and the U.K., official statistics do not provide information on active and recovered cases despite cases in these countries having been reported since March. The combined total COVID-19 cases for these four countries is over 3 million and accounts for 17% of the global total as of Dec. 21.

Filling the gaps

The University of Virginia’s COVID-19 dashboard recognizes the challenge that exists with active and recovered cases, attempting to estimate these numbers, as the researchers behind the dashboard believe it is a “more important metric to track than Confirmed cases.”

An algorithm designed to fill the gaps of recovered cases uses a median time from onset from COVID-19 to recovery for patients with mild cases as approximately two weeks, and three to six weeks for patients with more severe symptoms — with 81% of cases estimated as mild to moderate, 14% as severe, and 5% as critical. Where cases of recovery are reported locally and are higher than the modelled value, the reported value is used.

Using this methodology, the data suggests that as of Dec. 21, 65% of confirmed COVID-19 cases in Serbia should be considered recovered, 89% in Belgium, 69% in Sweden, and 78% in the U.K. Globally, it estimates 85% of confirmed cases to be recovered.

As the scientific knowledge base of COVID-19 continues to grow, this could be an interim solution until accurate data is available.