Catalan government will administer 1 million antibody tests to draw COVID-19 immunity map

The project aims to complement the available data on the spread of the virus

On Monday the Catalan government announced plans to administer one million serologic tests in order to draw up the map of COVID-19 immunity among the Catalan public, as reported by this newspaper last Sunday. The Catalan Health Ministry has revealed that the test —which detects the presence of virus-fighting antibodies— will be aimed primarily at health care professionals: 170,000 hospital and primary care staff across Catalonia.

So far several hospitals have already begun surveying their staff, including Barcelona’s Hospital Clínic and Parc Taulí in Sabadell. The results that this national plan is expected to yield will be used to determine the level of immunity among health care staff. The survey will also include staff employed in a range of hospitals and clinics, care homes and other facilities. Also included will be the entire workforce of the medical emergency service, as well as first responders like local and Catalan police officers who have been in close contact with patients, even though they are not employed by the health service.

While a calendar has not been decided yet, the plan is to evaluate the immunity condition of healthcare personnel over the next twelve months. Adrià Comella, the director of Catalonia’s Health Service, and Robert Fabregat, the general manager of research and innovation in health care, have explained that the plan will cost around €5M and that it aims to monitor the unfolding of the pandemic and to establish the profile of patients who recovered from the illness by place of residence, age, profession and underlying condition.

The healthcare executives have also indicated that they intend to test other grups, such as individuals who were suspected of having caught the disease and were dealt with as such, but were not given a PCR test for confirmation purposes, as well as the prison population. The testing will be conducted in several waves “to complement the data on the spread of COVID-19 and its evolution”.

Fabregat noted that the survey will allow the Catalan authorities to “draw a more accurate picture of the situation in Catalonia as a whole” and to compare the impact of the pandemic on certain groups and at the various stages in which the lockdown restrictions have been eased. For instance, they will be looking at the Òdena region, where the first critical outbreak was recoded in Catalonia, and Terres de l’Ebre, where COVID-19 has barely had an impact. Furthermore, the health authorities intend to test labourers currently working in Lleida’s fruit harvest. Fabregat pointed out that “these people have been living together in close quarters for some time and it is important to spot any new cases as soon as possible”.

Geographical differences

The results of this survey will complement the study by Spain’s Health Ministry, which kicked off a few weeks ago, whose preliminary results suggest that only six per cent of Catalans have tested positive for antibodies. This newspaper approached a number of experts who have indicated that Catalonia’s actual immunity figure might be higher because several areas that have been hit hard by the pandemic, such as Òdena, Barcelona city and the larger metropolitan area, were included in the results of one single province. Therefore, Madrid’s data could be skewed or biased.

Specifically, healthcare professionals will be tested in hospitals, whereas patients who presented with COVID-like symptoms but weren’t given a PCR diagnostic test will be given an appointment with their primary care centre for serologic testing. As for other groups, no decision has been made yet, but Fabregat said that one option would be for pharmacies to handle the tests.

This survey stems from a research project carried out by the Microbiology and Immunology services of Barcelona’s Hospital Clínic working with researchers from IDIBAPS, ISGlobal and Centre de Regulació Genòmica (CRG). Besides the Clínic, other Catalan hospitals that will also contribute to the project are Vall d'Hebron, Sant Pau and Hospital del Mar (Barcelona), Josep Trueta (Girona), Arnau de Vilanova (Lleida), Joan XXIII (Tarragona), Bellvitge (L'Hospitalet de Llobregat), Germans Trias (Badalona), Parc Taulí (Sabadell) and Althaia (Manresa). Catalan health ministry officials also indicated that a number of clinic laboratories will play a role in the study: Clilab Diagnostics (Consorci de Laboratori Intercomarcal de l'Alt Penedès, l'Anoia i el Garraf) and Cat Lab.

“Massive PCR testing makes no sense”

The general manager of research emphasised that primary care centres will play “a key role” in PCR and antibody testing, once the lockdown has been lifted. “Primary care facilities must drive this effort, whilst ensuring that they do not exceed their capacity. At the moment their main goal is to manage new cases and their contacts by means of PCR testing and do follow-up work on patients who reported symptoms in the last months by testing them for antibodies”, he insisted.

Catalonia’s PCR testing capacity has increased in the last few weeks, according to the health authorities. As the lockdown restrictions are progressively lifted, Fabregat estimates that the system could administer about 17,000 tests daily, a figure that will rise significantly over the next three or four weeks. However, Fabregat stated that testing volume will remain below capacity and that primary care centres will guarantee “that everyone who needs a PCR test, gets one” although “massive PCR testing makes no sense” as it is an unsustainable effort for any country. “Testing is not the solution to everything; instead, we need to bear in mind its intended purpose”, he said.

In order to ascertain whether someone is an active COVID-19 case, a direct test is needed and PCRs are the most reliable tool. In contrast, a form of indirect diagnostic tool is required in the case of patients who are recovering or have completely recovered from the disease. Serologic tests measure the antibodies produced by our immune system.