Reported new cases of infection doesn’t necessarily equate to newly infected people.
Patients retesting positive for Coronavirus anywhere in the world is a concern, especially where authorities had originally seemed to have the spread under control.
In the UK, according to the Office for National Statistics (ONS) as of 9am 19th April 372,967 people have been tested, of whom 120,067 tested positive, and 16,060 have sadly died. No data has yet been released to suggest reinfection.
In South Korea, according to the Korea Centres for Disease Control and Prevention (KCDC)163 people who tested positive, yet recovered from coronavirus, have retested positive.
Whilst CNN reports that, in China, although there are no official reinfection figures, some coronavirus patients are said to have re-tested positive after seeming to recover from their initial infection.
Although recovery rates vary according to different sources, just what does this suggest for the possibility of re-infection?
In an attempt to solve this mystery, the UK government has procured 3.5 million serology tests to measure blood plasma antibody levels, a key indicator of post-infection immunity. Antibodies are important because they can prevent a person from being re-infected with the same virus, as the body has learnt how to fight the disease.
Yet, World Health Organisation (WHO) spokesperson Maria van Kerhove has advised that there is no empirical evidence that these serological antibody tests can definitively prove whether those who have tested as positively infected, then become immune to reinfection.
Immunity versus contagion…
The UK Government has announced that it aims to be conducting 100,000 tests per day by the end of April, with 36 drive-thru test centres and counting. More tests will clearly provide health officials with additional data, the analysis of which can potentially provide a more accurate representation of whether or not those infected go on to develop a naturally acquired immunity.
In South Korea, however, the KCDC the said that so far, there’s no indication that the small number of patients who have retested positive are contagious – even though about 44% of them showed mild symptoms of the virus.
Reported new cases of infection doesn’t necessarily equate to newly infected people
South Korea’s recovered patients who have retested positive for the virus, have raised concerns about how antibodies work in response to Covid-19.
Although the cases that retest positive are relatively low, with only 2.1% of the 7,829 people who have recovered from coronavirus retesting positive; the KCDC have confirmed that as of yet, it is not clear how many of the people who have recovered have been tested again.
Similarly, in China, Officials in Wuhan Province recently re-submitted their death toll figures and, if the accuracy of the statistics reported from their Government weren’t already under enough scrutiny, it probably comes as no shock that a discrepancy of nearly 1,300 additional deaths was uncovered.
Nevertheless, patients retesting positive anywhere in the world is still a concern, more so in countries like South Korea where authorities had originally seemed to have the spread of infection under control.
Reasons for reinfection.
Many theories try to explain why the people of South Korea are now retesting as positive for the virus. Whilst some believe that there may be faults with some of the tests showing false positives, others suggest that maybe the virus is mutating and is not being correctly identified by the testing methods currently used.
CNN also reports that, alternatively, these new reports of reinfection could be explained by the reverse transcription polymerase chain reaction (RT-PCR) tests used, which work by finding evidence of a virus’s genetic information (RNA). Due to the sensitivity of these tests, it has been suggested that they could be detecting parts of a patients’ RNA, to the extent that, even after the person has recovered, they are providing positive readings.
The WHO advises that whilst it is “a good thing that so many tests are being developed around the world, they will need to be validated to establish whether they are measuring what they claim to be”.