The explosive delta variant of the coronavirus, first detected in India nine months ago and already prevalent on the planet, has transformed the war against the pandemic. The enemy has changed. The delta is almost twice as contagious as previous versions of the virus, as illustrated by the best-analyzed school outbreak to date: the one that occurred at the Nuestra Señora de Loreto Catholic school in Novato (California, United States). There, on May 19, an unvaccinated teacher with symptoms of covid continued teaching, even removing her mask from time to time to read aloud. In just one week, half of his 24 students had tested positive, even though the windows were open, the children did wear masks and there was an air purifier in the classroom. Delta leaves no room for mistakes.
Students of the
outbreak class
Students from other classes,
siblings and parents
The outbreak teacher started forced more than 230 people to test linked to the school. The virus infected at least 27. In addition to the teacher and 12 of her students, six children from the next class, four brothers and four parents of infected schoolchildren were infected.
* Day of symptom onset or sample collection
in the case of asymptomatic patients.
The study does not identify the sex of those infected.
Those infected with the delta variant of the virus become contagious two days before you have symptoms of covid and reach their peak of infectivity in the first days of illness. The teacher removed her mask at the worst moment.
Students of the
outbreak class
Students from other classes,
siblings and parents
The outbreak teacher started forced more than 230 people to test linked to the school. The virus infected at least 27. In addition to the teacher and 12 of her students, six children from the next class, four brothers and four parents of infected schoolchildren were infected.
* Day of symptom onset or sample collection
in the case of asymptomatic patients.
The study does not identify the sex of those infected.
Those infected with the delta variant of the virus become contagious two days before you have symptoms of covid and reach their peak of infectivity in the first days of illness. The teacher removed her mask at the worst moment.
Class students
outbreak
Students from other classes,
siblings and parents
The outbreak teacher started forced more than 230 people to test linked to the school. The virus infected at least 27. In addition to the teacher and 12 of her students, six children from the next class, four brothers and four parents of infected schoolchildren were infected.
An interaction between students could cause the jump to another class
* Day of onset of symptoms or sample collection in the case of asymptomatic patients.
The study does not identify the sex of those infected.
Those infected with the delta variant of the virus become contagious two days before you have symptoms of covid and reach their peak of infectivity in the first days of illness. The teacher removed her mask at the worst moment.
Class students
outbreak
Students from other classes,
siblings and parents
The outbreak teacher started forced more than 230 people to test linked to the school. The virus infected at least 27. In addition to the teacher and 12 of her students, six children from the next class, four brothers and four parents of infected schoolchildren were infected.
An interaction between students could cause the jump to another class
* Day of onset of symptoms or collection of samples in the case of asymptomatic patients.
The study does not identify the sex of those infected.
Those infected with the delta variant of the virus become contagious two days before you have symptoms of covid and reach their peak of infectivity in the first days of illness. The teacher removed her mask at the worst moment.
Epidemiologist Tracy Lam-Hine, lead author of the study of the outbreak in Our Lady of Loreto, believes that the case is a wake-up call, now that in many countries they are starting to go back to school after the holidays. “The most important lesson is that we cannot rely on just one layer of protection or even two. We have to use all prevention strategies at the same time, ”emphasizes the researcher, from the county Health Department.
All measurements must be used at the same time. If one fails, contagion can occur.
All measurements must be used at the same time. If one fails, contagion can occur.
All measurements must be used at the same time. If one fails, contagion can occur.
All measurements must be used at the same time. If one fails, contagion can occur.
The Spanish Association of Pediatrics has had to reinforce its own recommendations for going back to school in the face of “the irruption” of the delta variant, whose viral load in those infected is up to 1,000 times higher than that of previous versions of the virus, according to a study preliminary in China. If a covid patient infected two or three people on average at the beginning of the pandemic, now he can infect five, more than the flu. Spanish pediatricians have asked to keep the mandatory mask for children over six years of age, even during outdoor recess.
The fear is that the little ones will become a reservoir for the virus. 93% of those over 40 years of age in Spain are already vaccinated, but only 55% of children over 12 years of age have received the full schedule, as María José Mellado, head of Pediatrics at Hospital La Paz, in Madrid, recalls. There are still no authorized injections for those under 12 years of age, so none are vaccinated. “It is evident that, currently, the population most susceptible to becoming infected are children under 12 years of age and those older who have not yet completed the vaccination schedule,” warns Mellado, president until last June of the Spanish Association of Pediatrics.
The cumulative incidence at 14 days in adolescents is still soaring, with 193 cases per 100,000, more than double that of those in their sixties. However, coronavirus infection is usually asymptomatic or very mild in the very young. The data is relatively reassuring. Since June 20 there have been almost 315,000 cases in those under 19 years of age in Spain, with 1,900 hospitalized (0.6%), 91 admitted to the ICU (0.03%) and seven deaths (0.002%), according to the National Center for Epidemiology. Covid can strike healthy children, but above all it is a risk for those with previous illnesses and for unvaccinated adult relatives.
The Spanish Association of Pediatrics has regretted the decision of the Ministries of Health and Education to reduce the minimum distance between students from 1.5 meters to 1.2 meters, “which will lead to more children per class.” At the Nuestra Señora de Loreto school, distance was key. The teacher mainly infected the children closest to her, as shown by the comprehensive analysis of the outbreak, published on the website of the US Centers for Disease Control and Prevention.
Distance between students at school
where the outbreak occurred
In the last three rows, 4 out of 14 students were infected.
The contagion rate was 28%
In the first two rows, 8 out of 10 students were infected.
The contagion rate was 80%
Minimum distance between students in Spain
Distance between students at school
where the outbreak occurred
In the first two rows, 8 out of 10 students were infected.
The contagion rate was 80%
In the last three rows, 4 out of 14 students were infected.
The contagion rate was 28%
Minimum distance between students in Spain
Distance between students at school
where the outbreak occurred
Minimum distance between
students in Spain
In the first two rows, 8 out of 10 students were infected.
The contagion rate was 80%
In the last three rows, 4 out of 14 students were infected.
The contagion rate was 28%
Distance between students at school
where the outbreak occurred
Minimum distance between
students in Spain
In the first two rows, 8 out of 10 students were infected.
The contagion rate was 80%
In the last three rows, 4 out of 14 students were infected.
The contagion rate was 28%
Pediatrician Quique Bassat insists that it is still necessary to maintain these precautions in schools. “The worst thing that could happen to us is having a super contagious event like the ones in June in the Balearic Islands [con cientos de jóvenes infectados en viajes de fin de curso]. If we maintain strict measures until we have a much lower incidence, we will minimize this risk and, instead of waves, at most we will have self-limited outbreaks, “says Bassat, pediatrician at the Barcelona Institute of Global Health and coordinator of the Spanish Association of Pediatrics that has advised the Government for the return to schools.
Bassat calls on all school workers to get vaccinated as soon as possible if they have not already done so. The percentage of vaccinated teachers in Spain is very high, as suggested by the data from the communities that have given figures to this newspaper (95% in Extremadura, 94% in Aragon and 92% in Catalonia), but there are still thousands of teachers without immunization , like the teacher of Our Lady of Loreto.
The pediatrician believes that, to relax the measures, the cumulative incidence at 14 days should be less than 25 cases per 100,000 inhabitants, without notable outbreaks. Currently the incidence reaches 131 cases per 100,000, with outbreaks everywhere. Bassat would begin by eliminating regulations such as staggered entry into classrooms, shifts in the dining room, “obsessive hand hygiene with gel” and the prohibition of parents from accessing schools. However, he would keep the mask indoors until vaccination coverage was even higher and the cumulative incidence was “very very low, certainly less than 25 cases per 100,000.”
Bassat has two nine-year-old twin sons. “I will vaccinate them in the first moment that I can,” he says. The data shows that the Pfizer vaccine, the first licensed in the youngest, is very effective in those over 12 years of age in preventing serious cases. Covid hospitalization rates are 10 times higher among unvaccinated teens, according to the latest report from the US Centers for Disease Control and Prevention.
Pfizer is now testing its vaccine with 4,500 children between the ages of six months and 11 years – in Spain, the United States, Finland and Poland – and plans to request authorization for its use in the coming weeks. Other companies, such as Moderna and AstraZeneca, are also testing the effectiveness of their injections in minors. Some mathematical models calculate that group immunity to the delta variant will arrive when 85% of citizens are vaccinated, but children and adolescents under 15 years of age make up more than 25% of the world’s population. Vaccinating them could be essential to ending the pandemic.
* Investigators in the case do not detail the sex of the person who started the outbreak for privacy reasons, but the media national and locales in the US they have reported that she was a teacher.
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