Nội dung toàn văn Decision 3486/QD-BYT 2020 introducing interim guidelines for SARS-CoV-2 sample pooling
MINISTRY OF HEALTH
SOCIALIST REPUBLIC OF VIETNAM
Hanoi, August 07, 2020
INTRODUCING INTERIM GUIDELINES FOR SARS-COV-2 SAMPLE POOLING
MINISTER OF HEALTH
Pursuant to the Government’s Decree No.75/2017/ND-CP dated June 20, 2017 on functions, duties, powers and organizational structure of Ministry of Health;
At the request of the General Director of the General Department of Preventive Medicine and Ministry of Health,
Article 1. Promulgated together with this Decision are the interim guidelines for SARS-CoV-2 sample pooling.
Article 2. Interim guidelines for SARS-CoV-2 sample pooling shall be implemented in preventive healthcare establishments and healthcare establishments nationwide.
Article 3. This Decision takes effect from the date on which it is signed.
Article 4. Head of Office of the Ministry of Health; Chief Inspector of the Ministry of Health; heads of affiliates of the Ministry of Health; heads of Institutes of Hygiene and Epidemiology; heads of Pasteur Institutes; directors of hospitals affiliated to the Ministry of Health; Directors of Departments of Health; heads of health units of other ministries and central authorities; and heads of relevant units shall implement this Decision./.
P.P. THE MINISTER
SARS-COV-2 SAMPLE POOLING
(Promulgated with Decision No.3486/QD-BYT dated August 07, 2020 by the Ministry of Health)
I. GENERAL CHARACTERISTICS
COVID-19 is a group A acute infectious disease caused by the SARS-CoV-2 virus, which can be transmitted from human to human and has an incubation period of approximately 14 days. An infected person develops symptoms of acute respiratory infection such as fever, cough, throat pain, shortness of breath, potentially leading to severe pneumonia, acute respiratory failure and death, especially in those with underlying conditions or chronic diseases and the elderly. A large proportion of the infected shows no clinical manifestation (40-50%) and might become sources of infection in communities, posing challenges to monitoring and prevention. Currently, there is no cure or vaccine.
As of 6 PM 06/8/2020, there are 19.006.692 COVID-19 cases in 215 countries and territories with 711.876 deaths. Vietnam reports 747 cases with 10 deaths. Our country currently has 121 laboratories capable of performing SARS-CoV-2 Realtime RT-PCR tests. 537.000 samples have been tested with 747 samples testing positive for SARS-CoV-2. Positivity rate is approximately 0,1%.
These interim guidelines provide for sample pooling, which should save biologicals, chemicals and materials used for testing, reduce the amount of time required for testing and ensure testing quality based on actual demand, and shall be implemented by provincial governments, healthcare units and relevant units depending on the actual situation.
SARS-CoV-2 sample pooling has certain limitations such as having to recollect all samples from a pool testing positive for the virus. However, this will not cause much difficulty if the community positivity rate is low. Local governments and units must evaluate the COVID-19 situation regularly to consider applying sample pooling as appropriate.
- Support epidemiological monitoring and confirmatory COVID-19 testing in one or more than one population based on relevant risk factors and epidemiological assessment.
- Detect COVID-19 cases.
- Save biologicals, chemicals and materials used for testing; reduce the amount of time required for testing and enhance testing capacity.
III. GUIDELINES FOR SAMPLING, POOLING AND TESTING
- This procedure is applicable upon COVID-19 occurrence and shall be performed in qualified laboratories.
- The Realtime RT-PCR test shall be employed to detect SARS-CoV-2 antigens.
This procedure shall be performed in biosafety level II laboratories.
3. Testing quality assurance
Each laboratory shall formulate its own pool testing procedure.
4. Biologicals used for testing
Biologicals permitted by the Ministry of Health or appraised and recommended by the World Health Organization or U.S. CDC shall be used.
5.1. Sample types
Respiratory tract samples collected by trained personnel shall be used.
a. Upper respiratory tract samples:
+ Nasopharyngeal swab;
If nasopharyngeal swab cannot be collected, collect one of the following types of sample:
+ Throat swab;
+ Nasal swab (both nostrils), applicable to persons with suspicious symptoms;
+ Nasal/Nasopharyngeal wash;
+ Nasopharyngeal wash.
b. Lower respiratory tract samples:
+ Tracheal aspirate, broncheoalveolar lavage (BAL) fluid, pleural fluid, etc.;
+ Lungs, bronchi, trachea.
5.2. Sampling methods
a. Tool preparation
- Tools for nasopharyngeal swab, throat swab and nasal swab collection must not have a calcium or wooden handle; synthetic-tipped sticks are preferred.
- Tongue depressors;
- 15ml conical centrifuge tubes containing 2-3ml of viral transport medium;
- Plastic containers (Falcon 50ml tubes) or nylon bags for sample packaging;
- Bandages/Gauzes soaked with antiseptic;
- Antiseptic alcohol, pens
- Protective clothing;
- Safety goggles;
- Specialized medical masks (N95 or equivalent);
- Sterile 10 ml syringes;
- Sterile tubes without anticoagulant.
- Cold sample preserving containers.
b. Use of personal protective equipment
Step 1: Wash hands.
Step 2: Wear boots/shoe covers.
Step 3: Wear pants and gown (wear apron if required).
Step 4: Wear mask.
Step 5: Wear safety goggles (goggles with temples).
Step 6: Wear cap and make sure that it completely covers hair, head, ears and mask strings.
Step 6: Wear face shield or safety goggles (for goggles with strings to be worn outside of cap).
Step 7: Wear clean gloves.
c. Samples shall be collected in accordance with the guidelines enclosed with Decision No. 3468/QD-BYT dated 07/8/2020 and other relevant guidelines.
6. Sample pooling
6.1. Conditions for application of this procedure:
- Healthcare authorities shall decide to apply sample pooling based on actual situation, viral circulation and positivity rate.
- This procedure is applicable to asymptomatic cases during epidemiological monitoring in the community.
- This procedure is not applicable to:
+ Cases developing symptoms and cases having direct contact and facing high risk
+ Samples collected from persons who have undergone SARS-CoV-2 diagnostic testing but yet to receive the result.
+ Samples collected from COVID-19 patients currently receiving treatment.
+ Areas with high community transmission rate (evaluated and determined by Departments of Health).
6.2. Pooling method
- Step 1: Collect samples individually, draw up a sample list to divide the samples into groups of 5 and assign a code to each group (pool).
- Step 2:
+ Arrange the pools in ascending order of assigned code;
+ Prepare tubes containing 2-3ml of sterile viral transport medium and write the code of each pool on the tubes.
- Step 3:
Mix each individual sample evenly using a mixer/vortex mixer.
- Step 4:
+ Add 200 µl solution of every individual sample in a pool to one tube;
+ Close the tubes containing the pooled samples tightly
+ Preserve the individual samples (original samples) at – 40oC in case it is necessary to use them.
- Step 5: Perform a Realtime RT- PCR test on the pooled samples following the manufacturer’s guidelines.
7. Test result interpretation
- If the pooled sample tests negative for the virus, it means all individual samples in the pool are not infected with the virus and do not require further testing.
- If the pooled sample tests positive for the virus, it means at least 01 individual sample in the pool is infected with the virus. In this case, the laboratory shall:
+ Report the positive test result to its supervisory unit to evaluate the risk and take measures against COVID-19 as regulated.
+ Test each sample in the pool individually. If any sample tests positive for the virus, send the sample to a laboratory providing confirmatory testing (if this laboratory is not permitted to perform confirmatory tests) to confirm the result. Otherwise, recollect the samples, conduct laboratory tests on the samples following regular procedures, interpret the results and comply with reporting and COVID-19 prevention requirements according to regulations.
- If the test on the pooled sample gives uncertain result, repool the individual samples and test the new pooled sample in accordance with the guidelines provided for in parts 6 and 7 of Section III of these Guidelines.
8. Reporting requirements
Reporting requirements are provided for in the interim guidelines for COVID-19 monitoring and prevention promulgated together with Decision No. 3468/QD-BYT dated 07/8/2020 by the Ministry of Health and Circular No. 54/2015/TT-BYT dated 28/12/2015 by the Ministry of Health providing guidance on reporting and declaration of infectious diseases.
- Institutes of Hygiene and Epidemiology and Pasteur Institutes shall provide guidance and training concerning sampling, pooling and testing of pooled samples for local units to ensure quality and effectiveness.
- Steering Committees for COVID-19 Prevention and Control of provinces and cities shall direct sample pooling based on the epidemiological situation and facilities, equipment and personnel capacity of their respective provinces and cities.
- Centers for Disease Control and Prevention and laboratories capable of COVID-19 testing shall collect or receive samples, pool samples, perform tests and report as regulated.
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