Last weekend, the World Health Organization (WHO) received news of the next new variant of the Sars-CoV-2 virus – this time from Japan. “The more the virus can spread, the more likely it will be for further changes,” said WHO Director General Dr. Tedros Adhanom Ghebreyesus at a virtual press conference this week in Geneva.
As part of closer networks of research into variants of the virus worldwide, the WHO held a virtual conference involving 1,750 experts from 124 countries. Objective: to improve the monitoring of new virus variants. An interpretation of the effects on the course of the pandemic, on diagnostics, therapy and the effectiveness of the vaccinations is only possible if there is insight into changes in the virus. “Most importantly, we effectively sequence the virus so that we know how it changes and how to respond to it,” said the head of the WHO, providing, “While diagnostics and vaccines still appear effective with the current variants of the virus. virus., we may need to update them in the future. “
During the sequencing, a virus detected in the corona assay is checked at the molecular level, whose RNA strand consists of nucleotides, ie amino acids, with 29,903 individual positions. Even some mutations can be traced. At the beginning of last year, the D614G mutation was detected, which is now present in almost all virus sequences worldwide. In her case, the aspartic acid (D) in the 614th position on the so-called spiny protein of the virus was replaced by a reproduction error of a glycine molecule (G).
Codes for the new virus variants can be entered into the database of the internet platform gisaid.org and shared worldwide. “So far as many as 350,000 sequences have been publicly shared. Most, however, come from a handful of countries,” said epidemiologist Maria van Kerkhove, technical director of WHO’s Covid-19 division.
In December, the American microbiologist and pioneer of DNA-based vaccine research, Margaret Liu, cited a meticulous sequencing system in Britain as exemplary. There, approximately every 15th corona test is used for sequencing. In Germany, only every 900th test has been decoded at the molecular level so far.
Regardless of future virus variants, WHO chief Adhanom Ghebreyesus made two things clear during the press conference. Previous variants did not show an increase in the severity of the disease course. On the other hand, there is the fear that new variants will still lead to higher death tolls. The term virus variant is more accurate than the word mutation, because only the so-called British variant VOC 202012/01 (abbreviation of “Variant of Concern, year 2020, month 12, variant 01) has 23 individual mutations. The reason for the effects lies in that higher contagiousness of some variants. “That could trigger a new wave of illness and hospital admissions, which is problematic for staff and clinics at breaking point,” said the WHO chief.
British mathematician Adam Kucharski, who holds a PhD in mathematics, shows that a virus with 50 percent increased infectivity can ultimately be responsible for many more deaths than a virus with a 50 percent increase in its own death rate. Kucharski researches and teaches epidemiological dynamics at the London School of Hygiene and Tropical Medicine. His’ core message ‘is:’ An increase in something that is growing exponentially (such as proliferation) can have a much greater impact than the same proportional increase (50 percent in the calculation example) for something that measures only one result (the severity of the disease) . In his example, Kucharski assumes 10,000 infectious people, postulates an infection duration of six days, and initially applies a reproduction factor R of 1.1 (ten people infect 11 more). He also assumes an initial death rate of 0, 8 percent In the chosen sample scenario, 129 patients died after one month without any change. With a 50 percent increase in the number of fatalities from viruses, there are 193 deaths. With a 50 percent increase in infectivity, there are 978 deaths as due to a large number of extra patients, and the example calculation does not even include shifts in mortality rates due to extra overload in the clinics.
Independent of such calculation examples for new virus variants, WHO chief Adhanom Ghebreyesus emphasizes the importance of worldwide efforts to sequence the virus. In Germany, there are plans to expand sequencing: as the Ärzteblatt reported, referring to a concept from the Federal Ministry of Health, with every 20th corona positive PCR test.
Stricter inspection obligations for entries from corona risk areas
For trips to Germany from countries with a lot of corona infections, there will be stricter test obligations. Anyone who has been in a high-risk area in the past 10 days must submit a negative test no later than 48 hours after entry. This is regulated in a draft regulation by Minister of Health Jens Spahn (CDU), which the federal cabinet decided on Wednesday.
In areas with particularly high contamination levels or where new, more contagious virus variants are circulating, the test result must be available prior to entry and it must also be possible to present it to the airline. Travelers from risk areas are generally obliged to go into quarantine after returning. According to Spahn, virus mutations pose an additional health risk, so spread in Germany should be prevented as much as possible. The regulation will enter into force on Thursday. It also stipulates that from 1 March travelers must receive information via SMS about the measures in force in Germany to protect against entry and infection. Which countries are considered risk areas for German holidaymakers can be seen on an online list from the Robert Koch Institute. dpa