Another COVID Complication -- No Simple Solutions

"The finding does not mean taking vaccines will be useless. Immunity induced by vaccination can be different from those induced by natural infection."                  "The patient got re-infected 4.5 months after the first infection. Therefore, it shows that for this patient, the immunity induced by the first infection is short lasting."    Dr.Kai-Wang To, University of Hong Kong

"Given the number of global infections to date, seeing one case of reinfection is not that surprising even if it is a very rare occurrence."                                                  Jeffrey Barrett, consultant, COVID-19 Genome Project, Wellcome Sanger Institute, Britain

"This case illustrates that re-infection can occur even just after a few months of recovery from the first infection. Our findings suggest that SARS-CoV-2 may persist in humans, as is the case for other common-cold associated human coronaviruses, even if patients have acquired immunity via natural infection or via vaccination."                                                                                                   "Patients with previous COVID-19 infection should also comply with epidemiological control measures such as universal masking and social distancing,"                                                                                                     Research paper

Medical staff wearing protective clothing take test samples for the Covid-19 coronavirus from a foreign passenger at a virus testing booth outside Incheon international airport, west of Seoul, on April 1, 2020

"What I think is really important is that we put this into context. There's been more than 24 million cases reported to date. And we need to look at something like this on a population level. And so it's very important that we document this -- and that, in countries that can do this, if sequencing can be done, that would be very, very helpful. But we need to not jump to any conclusions."                                       "Even if this is the first documented case of reinfection, it is possible of course because with our.experience with other human coronaviruses, and the MERS coronavirus and the SARS-CoV-1 coronavirus, we know that people have an antibody response for some time but it may wane."                                           Maria Van Kerkhove, World Health Organization's technical lead for coronavirus response, head, emerging diseases and zoonoses unit

 

"The report from Hong Kong of a re-infection in a man by COVID-19 that was genetically different from the first infection should not be too surprising. It is, however, important that this is documented."

"Of particular note was that the case was a young and otherwise healthy person and that the second infection was diagnosed 4.5 months after the initial episode." "Commentators have been saying for some time that immunity is unlikely to be permanent and may only last a few months. Given the different intensity of the antibody response in people with mild or severe illness and the subsequent decay in levels, it is likely that those with a mild illness will have a shorter duration of immunity than those with severe illness."                                                                      Dr. Paul Hunter,  professor in medicine, University of East Anglia's Norwich School of Medicine, Britain

 

"Second infection was asymptomatic. While immunity was not enough to block reinfection, it protected the person from disease. Patient had no detectable antibody at the time of reinfection but developed detectable antibody after reinfection. This is encouraging. [Since reinfection can occur, herd immunity by natural infection is unlikely to eliminate the novel coronavirus.]"                          "The only safe and effective way to achieve herd immunity is through vaccination." "Lastly, while this is a good example of how primary infection can prevent disease from subsequent infection, more studies are needed to understand the range of outcomes from reinfection."                                                                                         Akiko Iwasaki. Yale School of Medicine

There have been reports from various countries; Israel, the Netherlands, of reinfections with COVID-19. People who had once contracted the disease then recovered months later being reinfected with an entirely new infection, and a new strain of the disease; meaning that the antibodies their immune system produced after their first infection were perhaps partially or temporarily effective in warding off new infection, but not long-lasting enough to prevent a future reinfection. This finding, should it turn out to be a common occurrence, would blow the effect of the herd immunity concept out of the water.

A 33-year-old man in Hong Kong, recovered from a bout of COVID-19, some four and a half months later was once again infected. His is the first documented case of human reinfection, and researchers at the University of Hong Kong, reporting on this case produced a study, published in the international medical journal Clinical Infectious Diseases. The man had been judged entirely recovered from COVID on his discharge from hospital in April.

He had later gone on a trip, returning on August 15 to Hong Kong from Spain through Britain. He appeared to be healthy but was found to have contracted a different strain of the coronavirus from that he had previously been infected with. For the second infection he remained asymptomatic, not knowing he was infected and theoretically passing the virus on to others with whom he came into contact. 

The virus which causes the disease has led directly to the deaths of over 800,000 people globally. And according to the findings documented in the newly published paper, COVID may continue to spread around the globe, in spite of herd immunity. The hope that the more people within any given population contracted the disease and community antibodies build, the better the opportunity for the greater, uninfected population to be able to avoid contracting SARS-CoV-2 causing COVID-19.

Dr. To, the lead researcher in the study, cautioned that no such predictions can yet be made with confidence, that results of the vaccine trials would determine just how effective they will turn out to be in preventing the further spread of the virus. Mainland China has reported instances of people having been discharged from hospitals after recovering from COVID-19 infection, later testing positive for the virus. There was no clarity however, whether the virus had been contracted following full recovery as with the patient in Hong Kong or whether these people had virus remaining in their body from the initial infection.

A man walks past a mural in Hong Kong on Sunday. | AFP-JIJI