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Information on the self-isolation rules for those testing positive for COVID.

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First published:
1 March 2022
Last updated:


24 February 2022


ATISN 15984 – Self isolation of close contacts

Thank you for your request to the Welsh Government for information under the Freedom of Information Act (2000) received on 20 January 2022.  You have requested the following:

  1. Evidence from TAG / TAC or a relevant body which formed the basis of the differentiation in rules surrounding self isolation of close contacts
  1. Evidence and / or an explanation as to why being boosted is not necessary in order to return to the workplace in such circumstances

Our Response

  1. As with all scientific and technical evidence provided by the Technical Advisory Group, there are other factors that need to be considered together with the science. When a policy decision is made, real life pressures arising from isolation, together with the need to balance harms will determine the policy. For this reason, the evidence provided below should not be considered the basis for differentiation of rules, but rather the available evidence to support decision-making.

The evidence from the Technical Advisory group to do with self-isolation is available here: technical-advisory-group-reduction-in-isolation-period-supported-by-LFT-for-cases-of-COVID-19.pdf (

While available data does suggest that the effect of boosters against symptomatic disease reduces over time, current evidence from UKHSA suggests that a booster remains 25-40% effective 10-14 weeks after vaccination. (Reference in TAC summary technical-advisory-cell-summary-of-advice-10-february-2022.pdf (

  1. Welsh Government does not hold the information you have requested. Vaccination or booster status is not a mandatory requirement for entering the workplace in Wales.

Next Steps

If you are dissatisfied with the Welsh Government’s handling of your request, you can ask for an internal review within 40 working days of the date of this response. Requests for an internal review should be addressed to the Welsh Government’s Freedom of Information Officer at:

Information Rights Unit, 
Welsh Government,
Cathays Park, 
CF10 3NQ 
or Email:

Please remember to quote the ATISN reference number above.

You also have the right to complain to the Information Commissioner. The Information Commissioner can be contacted at:

Information Commissioner’s Office, 
Wycliffe House, 
Water Lane, 

However, please note that the Commissioner will not normally investigate a complaint until it has been through our own internal review process.

Yours sincerely