Months after their first COVID-19 infection, patients in Hong Kong, the Netherlands and Belgium have again tested positive for SARS-CoV-2. Is there no lasting immune protection after surviving an infection?
Image: picture-alliance/dpa/S. Hoppe
Advertisement
In several instances, doctors reported possible reinfections during the pandemic. Mostly, however, they could not rule out that the second infection was not due to faulty testing procedures, false-negative test results or virus residues from the first infection.
A 33-year-old man from Hong Kong had mild COVID-19 symptoms in mid-March and tested positive for SARS CoV-2 on March 26. He remained in hospital until he was released on April 14 after two negative PCR tests.
Health authorities believe the man was infected a second time while on a business trip to Spain. A test conducted at Hong Kong airport on August 15 turned out positive. As a precaution, the man was taken to hospital again, although he showed no symptoms.
Genetic analyses showed he had contracted a mutated variant of the virus.
"The analyses showed that the first viral genome belonged to a different strain of SARS-CoV-2 than the second," said Dr. Kelvin Kai-Wang To, a clinical associate professor from the Department of Microbiology at the University of Hong Kong (HKU). According to the study, both virus variants differed in 24 nucleotides, the building blocks of the genetic material.
Hong Kong is relaxing its coronavirus measures and has lifted requirements for wearing masks outsideImage: Reuters/T. Siu
Scientists are aware that SARS-CoV-2 has mutated several times during the pandemic, repeatedly changing parts of its protein structure, as is common with viruses.
For the researchers, this case is clearly a new infection. Even after surviving COVID-19, it is still possible to become infected with a SARS-CoV-2 pathogen. Such reinfections also occur more frequently with other seasonal cold viruses such as coronaviruses 229E, OC43, NL63 and HKUI24, according to the Hong Kong researchers.
Two cases in Europe
According to Marion Koopmans, a virologist and adviser to the Dutch government, the genetic code of the second infection is also significantly different from that of the first, in the case of the patient in the Netherlands. It was an older man with a weak immune system. This speaks against a resurgence of the first infection, she added.
Mutations are likely the cause of the new infections. Image: picture-alliance/Geisler-Fotopress
Koopmans said it was not surprising that new infections were turning up among people who recovered from COVID-19.
"We know from other respiratory tract infections that one is not protected for life, and we do not expect this from COVID-19," the virologist said on Dutch radio.
However, it must now be clarified whether such repeat infections actually occur more frequently or whether they are isolated cases.
In Belgium, one patient took ill again after three months. A gene sequence analysis also revealed that the virus had 11 mutations in the second case. "This is not good news," said virologist Marc Van Ranst on the Belgian channel VTM.
Advertisement
Many open questions
The apparent reinfections add to indications that immunity to SARS-CoV-2 is short-lived. Even after surviving the COVID-19 disease, at least some patients have only partial protection. Not all of them seem to develop protective antibodies.
However, even eight months after the outbreak of the pandemic, many questions remain unanswered, and it is difficult for researchers to gain an overview of the details of global infections as research is conducted worldwide, with many results published quickly and without the necessary peer review.
Detailed studies on the cases in the Netherlands and Belgium are not yet available. There are also only excerpts from a specialist article on the documented repeat infection in Hong Kong that a reporter from the South China Morning Post posted on Twitter. These results have not yet been subject to peer review.
What does this mean for a vaccine?
More than 150 vaccines against SARS-CoV-2 are currently being developed worldwide. Recently, Russia has approved the vaccine "Sputnik V," and seven other vaccine candidates are in the decisive clinical Phase III tests.
If reinfections are indeed confirmed, SARS-CoV-2 is unlikely to disappear due to effective herd immunity. It is also possible that vaccines currently in development may not provide lifelong protection against the aggressive coronavirus.
Until Phase III clinical trials are completed and meaningful long-term studies are available, it is not possible to make reliable statements about how effective these vaccines are, whether they will protect against viral mutations or how long the protection will last.
Coronavirus brings back-to-school challenges
As school holidays wind down around the world, COVID-19 infections are once again on the rise in many countries. In an effort to avoid further shutdowns, schools have adapted their approach to in-class learning.
Image: Getty Images/L. DeCicca
Thailand: Class in a box
The roughly 250 students who attend Wat Khlong Toey School in Bangkok now sit in plastic cubicles during class, and must keep their face masks all day. Sinks and soap dispensers are positioned outside each classroom, and temperatures are taken as students arrive to school in the morning. The strict measures seem to be working: the school has reported no new infections since July.
Image: Getty Images/L. DeCicca
New Zealand: School for some
These students in the capital, Wellington, are happy they can still go to school. Those in Auckland aren't so lucky. After the country went virus-free for three months, four new cases were reported in the country's largest city on August 11. Health authorities ordered the closure of schools and non-essential businesses in the city, and told citizens to stay home.
Image: Getty Images/H. Hopkins
Sweden: No special measures
Students in Sweden are still enjoying their summer holidays, but this picture of graduates taken before the break continues to symbolize the country's special approach to dealing with COVID-19. Unlike almost everywhere else in the world, the Scandinavian country has never required citizens to wear masks. Businesses, bars, restaurants and schools have all remained open.
Image: picture-alliance/AP Photo/TT/J. Gow
Germany: Single file, at a distance
These students at Petri Primary School in Dortmund, North Rhine-Westphalia, are exhibiting exemplary behavior. Like all schools in Germany's most populous state, theirs requires face masks. Yet unlike students in Germany's other 15 states, they must also wear them in the classroom. It's too early to tell if the measures are working, however — the school year only kicked off on August 12.
Image: Getty Images/AFP/I. Fassbender
West Bank: Back to school after 5 months
School has also resumed in Hebron, some 30 kilometers (19 miles) south of Jerusalem. Students in the region are required to wear face masks, with some schools even calling for gloves. Yet despite her mask, this teacher's enthusiasm is evident. Schools in the Palestinian territories have been closed since March, with Hebron being an epicenter of infections.
Image: Getty Images/AFP/H. Bader
Tunisia: Masked since May
This class of high school students in Tunis began wearing masks in May. As schools across the North African country resume in the coming weeks, all students will be required to wear them. When Tunisia's schools were closed for several weeks in March, parents had to school their children at home, helping them with TV and internet-based learning programs until classes could resume in early summer.
Image: Getty Images/AFP/F. Belaid
India: Teaching by loudspeaker
This school in Dandwal, in the western Indian state of Maharashtra, has a special setup for students who have no access to the internet. Here they can attend a type of tutoring session to catch up on missed assignments, listening to prerecorded classes over a loudspeaker. Maharashtra was particularly hard hit by the coronavirus pandemic.
Image: Reuters/P. Waydande
Congo: No class without temperature check
Authorities in Lingwala, a well-heeled suburb in the Congolese capital, Kinshasa, are taking the threat of coronavirus infections among students extremely seriously. Every student attending the suburb's Reverend Kim School is required to have his or her temperature taken before being allowed to enter the building. Face masks are also mandatory.
Image: Getty Images/AFP/A. Mpiana
United States: Lessons in the world's hot spot
Schools in the US are also doing daily temperature checks to detect potential COVID-19 cases. Such measures are urgently needed in the country, which continues to see some of the world's highest infection rates. On August 13, Johns Hopkins University reported that more people had died within the past 24 hours than at any point since late May.
Image: picture-alliance/Newscom/P. C. James
Brazil: Gloves and a hug
Maura Silva (left) is a teacher at a public school in western Rio de Janeiro, near one of the city's largest slums. She makes an effort to visit her students at home, and brings along her "hug kit." Before taking them in her arms, Silva and her students put on masks and she helps them to put on plastic gloves.
