TEACHERS' risk of being hospitalised with Covid more than doubled after remote learning ended and schools in Scotland reopened for the autumn term last year, according to a new study.

Researchers also found that teachers working in secondary schools were more likely to end up in hospital with the virus than those working in primary or nursery school settings.

However, they caution that over the course of the pandemic as a whole, including when schools were open, teachers were at lower risk of severe Covid resulting in an intensive care admission than the general population.

Their overall incidence of a hospital admission between March 2020 and the end of July 2021 was also similar to the average for working age adults, at less than one per cent.

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The authors of the study, published today in the British Medical Journal (BMJ), said their findings "should reassure most adults engaged in in-person teaching".

The research, led by scientists at Public Health Scotland and Glasgow University, identified 128 hospital admissions, including 15 ICU admissions, among teachers over the study period.

Demographically, teachers had an average age of 42, 80 per cent were female, and 84% had no co-morbidities.

Once the data was adjusted to account for variables such as age, sex, ethnicity, deprivation and pre-existing illness, teachers still had a 50% lower likelihood of being hospitalised with Covid during the period when schools were closed in spring and summer of 2020 compared to other working age adults aged 21 to 65.

In comparison, patient-facing healthcare workers were nearly four times more likely than the general population to be hospitalised with Covid during this period.

However, when the researchers compared the risk of hospitalisation among teachers specifically between the spring/summer term when schools were closed and the autumn term when in-person teaching resumed, they found it was 2.4 times higher.

"This increase suggests that the risk to teachers during the autumn 2020 term was similar to that in the general population," they add.

Overall they found that secondary school teachers were roughly 35% more likely than other working-age adults to be hospitalised with Covid during this time, while primary school teachers were either at the same or lower risk - although the researchers noted that the margin of error for these estimates "was wide" due to the low number of hospitalisations involved.

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By the time schools had fully reopened for the summer term in 2021, when the Delta variant was spreading but vaccine rollout was at an advanced stage, teachers overall had a 15% lower risk of being hospitalised with Covid compared to the general working population.

Nonetheless, they were still 1.7 times more likely to have been hospitalised during this period than when schools were closed at the beginning of the pandemic.

No increased risk of severe Covid was found for any in any period, whether schools were closed or open.

HeraldScotland: Source: 'Rise of hospital admission with Covid-19 in teachers...in Scotland' (BMJ)Source: 'Rise of hospital admission with Covid-19 in teachers...in Scotland' (BMJ)

The researchers noted that similar research in Sweden had found that secondary teachers who taught in person were twice as likely to test positive, be hospitalised, or die from Covid compared to those teaching remotely, but added that this may be evidence of the "protective effect of working at home rather than a harmful effect of working in a school setting".

They add: "These findings are consistent with our own observations that the rate ratio for hospital admission with Covid-19 for teachers is close to one when schools are opened but close to 0.5 when schools are closed."

The researchers said there were several "plausible" explanations for why hospitalisations were lower among teachers than the general working age population when schools were closed.

They suggest that teachers may be "more rigorous" than other adults in observing social distancing and ventilation guidance, or they may have different lifestyle habits which could not be adjusted for in the study - such as lower smoking rates, healthier diets, or better exercise levels - which reduce their risk of becoming seriously ill from a Covid infection. 

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Prior exposure to other respiratory viruses from years of working in school environments was also put forward as a possible source of increased immunity. 

They continue: "Teachers might have more efficient immune responses after exposure to SARS-CoV-2 [coronavirus] owing to the presence of cross reactive T cells from increased previous occupational exposures to viruses.

"Finally, during periods when schools are closed, teachers might have low numbers of contacts compared with other adults of working age, such that, even where they have similar underlying health, teachers are at lower risk of Covid-19.

"Some support for this last suggestion comes from the finding that working exclusively from home is associated with a lower risk of Covid-19, and in our view this is the most plausible explanation for the lower risk among teachers during the period when schools were closed.

"This latter explanation is also consistent with the observation that when teachers returned to in-person teaching, the risks of hospital admission with Covid-19 were observed to increase."