This evidence review was compiled by members of the CITF Secretariat with the input from experts affiliated with the CITF and does not necessarily reflect the views of all CITF members.

By Mercedes Yanes Lane

On September 20th, 2021, Pfizer-BioNtech announced preliminary results from its phase 2/3 trial in children ages 5 to 11 with a two-dose vaccine scheme.1 With this information, regulatory agencies can now assess the safety and efficacy of the vaccine on their end with the aim of approving the lower dose of this vaccine in children. However, non-vaccine strategies need to remain in place to ensure that all schools remain safe environments. Which non-vaccine strategy to choose? One study in the UK provided a pathway to limit school disruptions by using a testing strategy.2

Providing a safe school environment during this back-to-school period is one of the main concerns for both governments and families. To do so, strategies are needed to reduce COVID-19 cases in schools.

In the UK, researchers tested two possible testing strategies. They led a randomized control trial in which they assigned schools to one of two strategies for when students or staff were in possible contact with a COVID-19 case: a) daily testing over seven days and continued school attendance, or b) 10-day quarantining. Contacts were offered daily contact testing as an alternative to quarantining, provided that the following criteria were met: the contact was school-based (i.e., a staff member or student), they did not have COVID-19 symptoms, and they were able to get on-site testing at school. Testing was carried out using a rapid antigen test and nasal swabbing.

Key findings:

  • A total of 201 schools actively participated in this study. Both secondary schools (students aged 11 to 18 years) and post-secondary institutions participated.
  • In the control group (the group choosing to isolate at home): 4,463 people within 47 schools were deemed to have been in contact with a COVID-19 case. This translated to 22,466 school days for which students and/or staff were asked to isolate at home.
  • In the testing group (the group choosing to be tested daily for 7 days): 5,763 people within 59 schools were deemed to have been in contact with a COVID-19 case. This would have translated to 27,973 school days for which, without testing, students and/or staff would have quarantined.
  • Students from the control group had 1.80% COVID-19-related absences, compared to 1.47% in the testing group.
  • Transmission was not higher in schools using the testing strategy.

This study provides evidence that daily contact testing is a safe alternative to home isolation in school-based contacts. As such, this strategy could be an effective way to increase school attendance in secondary level educational institutions.


  1. Pfizer and BioNTech Announce Positive Topline Results From Pivotal Trial of COVID-19 Vaccine in Children 5 to 11 Years. 20 September 2021. Available at
  2. Young BC, Eyre DW, Kendrick S, White C, Smith S, Beveridge G, Nonnenmacher T, Ichofu F, Hillier J, Oakley S, Diamond I, Rourke E, Dawe F, Day I, Davies L, Staite P, Lacey A, McCrae J, Jones F, Kelly J, Bankiewicz U, Tunkel S, Ovens R, Chapman D, Bhalla V, Marks P, Hicks N, Fowler T, Hopkins S, Yardley L, Peto TEA. Daily testing for contacts of individuals with SARS-CoV-2 infection and attendance and SARS-CoV-2 transmission in English secondary schools and colleges: an open-label, cluster-randomised trial. Lancet. 14 Sep 2021:S0140-6736(21)01908-5. doi: 10.1016/S0140-6736(21)01908-5.