More than 500 introductions in Spain: this is how the coronavirus nightmare began

Biblical experts know how important misprints are in determining the age of a copy.

The royal printers of London, for example, in 1631 ate the word "no" when copying one of the ten commandments, the seventh, which was published thus: "You shall commit adultery."

Just looking at that failure, any researcher would think of the so-called adulterous bible of the seventeenth century.

The new coronavirus, like biblical copyists, is very good at making copies of itself, but from time to time it also misses the 30,000 chemical letters of its genome, so scientists can inspect those errors to piece together its history.

An October virus is about 20 mutations away from the first ones studied at the start of the pandemic.

The genetic analysis of the coronavirus of 2,170 patients, the largest carried out to date, has identified at least 519 independent introductions of the virus in Spain during the first wave, most from mid-February.

Researchers point to "multiple entries by Valencia" after the Atalanta-Valencia football match, played on February 19 in Milan, which was attended by some 2,500 Valencian fans.

The scientists also suggest a relevant role for Milan Fashion Week, held from February 18 to 24 with Spanish visitors, and for the international contemporary art fair ARCOmadrid, inaugurated on February 27 at IFEMA, the same Madrid fairgrounds. that a month later it would be converted into a hospital for covid patients.

"There is no zero patient," emphasizes the report, prepared for health authorities by a team led by biologist Iñaki Comas, from the Institute of Biomedicine of Valencia (CSIC).

The authors have identified two genetic families, called SEC7 and SEC8, which are "the main groups causing the epidemic in Spain", concentrating the highest number of infections: 10% and 30%, respectively.

SEC8 came to represent 60% of the cases sequenced in the first weeks of March.

Both families correspond to strains of the virus circulating in China at the beginning of the pandemic.

"This suggests that the introductions occurred very early in Spain", while in Europe other later types predominated, the authors point out.

A genetic family of the coronavirus, baptized SEC8, came to represent 60% of the cases sequenced at the beginning of March

The European Center for Disease Prevention and Control already warned on January 18 that the Wuhan airport (China) had six direct weekly flights to Paris, three to Rome and another three to London.

The Spanish Government decreed a state of alarm on March 14, imposing the isolation of millions of people in their homes and the border shielding.

"A stricter border control, together with early and local mobility closures, probably would have limited the expansion of SEC8 and, therefore, of the epidemic in Spain," says Comas' team.

The report recalls that the oldest covid case in Spain was that of a 69-year-old man who returned on January 30 from a trip to Nepal and died on February 13 from pneumonia in a hospital in Valencia.

“However, the identification of an early case does not imply that the patient in question is the generator or initiator of the pandemic in Spain.

In fact, neither in the epidemiological studies nor in our analyzes did this patient generate any secondary cases, ”the scientists explain.

That case from Nepal "left no trace," according to investigators.

Iñaki Comas's team has crossed the results of genomic analyzes with the scarce epidemiological data to try to explain "how a few cases can turn into thousands in just a few weeks."

Their report notes that the SEC8 variant was soon introduced from Italy via Valencia and Madrid, and possibly other cities, and spread rapidly thanks to various "local super-dispersion events", such as a funeral in Vitoria on February 23, with more than 60 infected people among the attendees and their close contacts.

The SEC8 family, surprisingly, does not have the D614G mutation, a single letter change in the virus genome that some scientists believe is associated with an increased ability to infect.

“We have not detected any type of specific mutation [linked to higher transmissibility].

The success of a mutation has more to do with opportunity: being in the right place at the right time, ”says Comas.

"Everyone has arrived late in this pandemic, including us with this report," admits biologist Iñaki Comas

These dominant genetic variants in the first wave are now, however, very residual.

"Virtually all have become extinct, indicating the great success that the lockdown represented," say the researchers, who have preliminary data that new groups have replaced those of the first wave.

Spain is the second European country and the fourth in the world in number of sequenced virus genomes, mainly thanks to the SeqCOVID consortium, led by Iñaki Comas and by the geneticist Fernando González Candelas, professor at the University of Valencia.

However, its results have come with a long delay, according to Comas himself.

"Everyone has been late in this pandemic, including us with this report," admits the biologist.

His dossier lists “a whole series of problems” that have prevented the rapid generation of data.

“Real-time information, as in the UK, requires available staff who are dedicated full time to generating reports.

SeqCOVID does not have this staff due to lack of budget ”, criticizes the document, which bears the seals of the CSIC and the Ministry of Science.

The report also regrets the lack of access to patient samples, due to the overload in hospitals during the pandemic, and especially to their epidemiological data: where and with whom were these people in the previous days.

“For most cases we only have a limited number of variables collected.

Linking these cases to epidemiological data is almost impossible given the great variety of institutions that must be involved to obtain them ", the authors acknowledge in their report.

"There is no epidemiological surveillance structure with genomes in Spain," says Iñaki Comas, who asks the authorities to set themselves the objective of achieving this surveillance "in real time."

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