Covid-19 rates amongst incoming travellers

WQ.328/2020

WRITTEN QUESTION TO THE MINISTER FOR HEALTH AND SOCIAL SERVICES BY DEPUTY J.H. PERCHARD OF ST. SAVIOUR

ANSWER TO BE TABLED ON TUESDAY 22nd SEPTEMBER 2020

Question

Further to the Assembly's adoption of A safer travel period: States Assembly approval' (P.84/2020), as amended, ahead of which States Members and the public were advised to expect one case of Covid-19 every 7 weeks once the borders were re-opened, will the Minister advise –

1. what explanation, if any, has been identified for the underestimate of the number of incoming cases;
2. who was responsible for the estimate of one case in every 7 weeks;
3. what action, if any, has been undertaken to correct the estimate in light of the experience to date;
4. what the expected number of cases entering the Island each week now is; and
5. at what number of cases entering the Island each week the Government will consider –

1. the closure of the borders; and
2. the enforcement of self-isolation for everyone awaiting a test result?

Answer

1. The Scientific Technical Advisory Cell's original estimate was based on the Office of National Statistics' assessment of live infection prevalence in England as of June[1]; evidence about the proportion of asymptomatic cases; and data related to the likelihood of onward seeding of infection and the efficacy of PCR testing at the border. English prevalence at the time was 1:1700. The table below [in part d] shows 73,889 arriving passengers from the start of July to the 13th September, with a total of 49 positive cases which is a rate of approximately 1:1500 cases[2].
2. The original estimate of one case in every seven weeks was referring to the anticipated rate of onward transmission from an incoming passenger who is positive before they got their result (based on 1000 arrivals per week). This estimate remains an accurate assessment.
3. In response to the increase in national and international rates of infection, the Medical Officer of Health has routinely reviewed country risk assessments and also brought forward a regional approach for passengers arriving from countries which represent the most frequent traveller activity. This has allowed a more targeted application of the test and isolate regime to passengers entering the Island from areas of higher risk.

4. Below is the table of weekly travellers and the number of positive inbound travellers who were active at the time of detection [3][4] . In more recent weeks, there has been more testing than arrivals due to a higher number of travellers arriving from Amber areas and requiring a Day 5 test. For every positive inbound traveller case, there is on average 10 direct contacts.

5. The Safer Travel Policy Covid-19 Strategy sets out a consistent approach and response to the increase in new cases within countries and regions. The policy objective continues to support safe travel and to allow Islanders to visit relatives who live off-Island and support local business. Broader public health measures such as on-island testing, increased tracing capacity and establishing enforcement continue to play an important role in ensuring the number of cases on-Island resulting from travel remains low.

There are no precise numbers at which the initiatives mentioned by the Deputy would be triggered. The policy and the data remain under constant review. This week, Ministers have asked officers to consider applying regional classifications to English lower-tier authorities. This may better reflect the distances between higher and lower levels of infection in county areas and may stop the scenario where higher infection rates in larger county towns could be masked by lower infection rates in the surrounding countryside.