Criteria for mandatory testing have changed throughout time. Initially, passengers from high-risk countries with symptoms were tested. Until February 19, 23 persons arriving from China were tested. At the beginning of March, the National Operations Headquarters decided to test also patients with viral infection hospitalised in the infectious disease’s wards. After diagnosing the first cases on March 8, the scope of testing was changed to include suspected cases. The close contact persons have been tested, as well. Until March 27, approx. 6,500 laboratory tests were performed, using the PCR method. On April 10, the number of performed PCR tests reached 18,502 or above 2,640 per 1 million population. Most recently, drive through testing has also been implemented for health care workers.
Testing can be requested by health care establishment (hospitals and GPs) and RHIs (for contact persons). In such cases, the tests are paid through public sources. Some private diagnostic laboratories perform rapid tests, but they are requested and paid by the patients (approx. EUR 15).
COVID-19 laboratory testing capacity has grown as required. Initially, all tests were conducted in the National Reference Laboratory for Influenza and Acute Respiratory Diseases to the National Centre of Infectious and Parasitic Diseases (the first test was performed on January 28); 5 days later (on February 2), the second laboratory in Sofia started to perform PCR tests for COVID-19. Until the end of February, another two laboratories were accredited to conduct tests with a total capacity of 100-150 tests daily. By the end of March, Bulgaria had eight laboratories to which samples were submitted for analysis. At the beginning of April, another three laboratories were prepared, and it is expected the daily capacity of tests to increase to 2,500. Laboratory capacity is assessed as sufficient, but there are some concerns about the shortage of tests.
Since the epidemic onset in Bulgaria, several panel testing schemes have been carried out among police officers, navy and military servicemen, medical personnel and some municipal employees engaged in social services and disinfection initiatives. Moreover, mass testing of settlements and neighbourhoods under quarantine was conducted using serological tests and confirming positive results with PCR testing.
Testing capacity has further been increased to 18 laboratories throughout the country provided RT-PCR diagnostic by mid-April. Up to April 22, in total about 27,000 PCR tests had been conducted (above 3,800 tests per a million population). In addition, private laboratories reported more than 2,300 antibody tests paid out-of-pocket by citizens. The National Operational Headquarters considers starting mass-testing for medical personal, patients with pulmonology diseases in mild conditions and employees of essential sectors such as energetics. The target is to conduct more than 7,000 tests or 1,000 tests per a million population weekly. The results will also be analysed in the context of the possible impact of vaccination policy on the infection transmission and severity of disease (for many years, Bulgaria has had compulsory vaccination programs against several communicable diseases).
Testing capacity has been expanded to 24 laboratories for RT-PCR diagnostic throughout the country. Up to May 7, in total around 53,000 PCR tests had been conducted (above 7,500 tests per a million population), reaching the target of more than 1,000 tests daily. Mass testing in the second-largest city in Bulgaria, which is moderately affected by the COVID-19 epidemic, is going to be carried out in the next weeks using ELISA method. The results should contribute to the epidemic spread and immune response modelling.
By mid-June, testing capacity has been expanded to 36 laboratories for RT-PCR diagnostic, resulting in an almost twofold increase in daily performed PCR tests. Up to June 17, around 15,500 tests per a million population had been conducted, exceeding 2,000 tests daily. The number of antibody tests also increased over the last weeks. Meanwhile, mass testing in the second-largest city in Bulgaria, initiated in May, reveals that less than 2% of around 1,200 randomly selected people have antibodies to SARS-CoV-2.
In October and November, the laboratory capacity was further enhanced, reaching 75 laboratories certificated for PCR testing throughout the country. At the beginning of November, the number of conducted PCR tests increased to more than 10,000 per day, and the total number of PCR tests exceeded 120,000 per 1 million population. Nevertheless, by the RT-PCR testing rate, Bulgaria still lags behind many European countries.
Antibody testing has been initiated in triage offices established to the district hospitals as well as to COVID-19 zones (medical offices) to the diagnostic-consultative centres. Antibody tests are conducted at the physician’s discretion free for patients.
As of December 22, 2020, the rapid antigen tests have been added to the laboratory criteria in the definition of a COVID-19 case, and thus, the results of these tests have been included in the national statistics of newly registered cases. Persons with positive antigen test results have to be reported as confirmed cases of COVID-19 in the Unified Information Portal and are subject to 14-day isolation with anyone they came in close with subject to a 10-day quarantine. The same order applies in the cases confirmed by PCR tests. For persons with clinical symptoms but negative antigen test results, a PCR test has to be carried out. Until mid-December 2020, more than 1,200,000 antigen tests had been conducted; however, these results will not be included retrospectively in the official statistics of confirmed COVID-19 cases in Bulgaria.
By the end of December 2020, laboratory capacity had been further expanded and almost 100 laboratories throughout the country were certificated for processing PCR tests for COVID-19.
At the end of January 2021, the mass testing of teachers and non-teaching staff at schools with rapid antigen tests was initiated, aiming to identify possible hidden morbidity before the resumption of in-person classes for students from 5th to 12th grades (scheduled for February 4, 2021 – see 1.2 Physical distancing). The testing of staff was voluntary and free of charge. Mass testing for COVID-19 was performed for the staff in kindergartens, as well.
According to an order of the Minister of Health, school and university students from neighbouring countries who travel to Bulgaria every day or at least once a week for educational purposes, are not required to present PCR-test results when entering Bulgaria.
Sources and links:
Ministry of Health; https://www.mh.government.bg/bg/
Informational Portal for COVID-19; https://coronavirus.bg/