Saturday, January 28, 2023

SENTINEL Surveillance: An Alternative Method to Track COVID-19

By on June 12, 2020

By Nabal Bracero, M.D., F.A.C.O.G.

The COVID-19 pandemic has made the world reflect on the importance of having a robust and agile public health system. The doubts and questions that have emerged about this devastating virus are understandable given the speed of its spread, severity of the disease and the initial lack of evidence and knowledge about its prevention, management and tracking. An analysis of the public health response to COVID-19 demonstrates weaknesses and confusions inherent to the testing system used to identify infected and/or infectious patients. Until now, multiple different types of tests (serological/antibodies (IgM, IgG), molecular/nucleic acid (PCR/RNA) and antigens) have been used, following protocols with criteria depending on the availability of the test and variables such as the presence of symptoms, risk factors, contact with sick individuals, or as a requirement to be able to proceed with scheduled surgeries and returning to work.

To prospectively understand and document the impact of SARS-Cov-2 in the population, it is necessary to systematically investigate and establish the incidence and prevalence of this virus among asymptomatic individuals in the general community. To face the paucity of evidence, the complexity of access to clinical services, and to avoid further interruption of economic activity, a dynamic asymptomatic sampling model should be sought, adaptable to the existing health system. For these purposes, we propose to implement a SENTINEL surveillance system, a well-known tool in epidemiology. SENTINEL surveillance systems allow identification of regional foci of infection by testing an asymptomatic portion of the general population, without having to intervene with the whole community. Applying statistical prediction models, scientific analysis can allow extrapolating SENTINEL data to the general population.

It is necessary to be prudent and cautious, and remember that effective vaccination and treatments against COVID-19 can take much longer than desired or predicted. Furthermore, we still need to learn a lot more to determine the future trajectory of SARS-Cov-2. Therefore, we need appropriate tools to continuously monitor this virus. For example, the epidemiological trends of sexually transmitted diseases such as syphilis and HIV are estimated and monitored using SENTINEL groups such as individuals seeking a marriage license. SENTINEL groups can be composed of patients who have consistent interaction and access to the health system. People can obtain a clear clinical benefit, with possible changes in their medical management, depending on the result of the COVID-19 test. Ideally, these subjects do not add significant additional risks or discomfort to their normal health care routine. Some examples of SENTINEL groups may include nursing home residents, patients on dialysis or chemotherapy, people scheduled for surgical procedures, and PREGNANT women close to delivery time.

The more representative of the average risk of infection behavior, and the broader the geographic and age diversity, the stronger the data acquired. 

Recently, the Puerto Rico Department of Health, PROGyn (Puerto Rico Obstetrics and Gynecology), a local non-profit, ACOG (American College of Obstetricians and Gynecologists) PR Section, and others have come together to develop CASSS (COVID-19 Antenatal Sentinel Surveillance System). CASSS project has the objective of securing uniform and universal COVID-19 testing for all pregnant women, asymptomatic and symptomatic, in Puerto Rico. In a collaborative effort among private clinical laboratories, obstetrical clinics, labor room units, obstetricians and public health agencies, CASSS intends to improve clinical care of both mothers and newborns, while establishing a SENTINEL surveillance system for COVID-19. We recognize it would be ideal to test pregnant patients for COVID-19 in all three trimesters to learn and gather solid data on the impact of this virus on gestation. Yet, in view of limited testing capacity, at this time, COVID-19 pregnancy protocols in Puerto Rico recommend the following:

  1. To order COVID-19 test, both serological and molecular, between 35-37 weeks as described in the CASSS project.
  2. To order COVID-19 test, both serological and molecular, according to the laboratories series of any admission to the hospital or labor and delivery unit (i.e. antepartum for obstetric care, electively for induction of labor or cesarean section, active delivery, etc.) expanding on CASSS.
  3. To comply with Department of Health Administrative Order 426 that requires all obstetricians and clinical laboratories to report all results of COVID-19 TESTS ordered to pregnant patients.

Several clinical laboratories in the community, hospital system and the Public Health Laboratory of the Department of Health are already participating in these initiatives and will give priority to the processing of samples from pregnant patients. We are recommending two types of tests (serological and molecular), and TWO sampling times (at 35-37 weeks and closer to delivery) for several reasons: to understand both the immune reaction and the physiology of the virus among expecting mothers; to accommodate to different protocols and resources of each hospital and obstetrician; to investigate better the progress and behavior over time of COVID-19; to have more than one opportunity to screen in case the other fails; and at the time of delivery to inform better the delivery room team, nursery and the patient of her status and the baby’s status. These efforts are voluntary and each patient and their caregivers should discuss the implications of the results of these tests for SARS-Cov-2. However, we understand that this information is valuable to families and the community at large. Thus far, we have tested close to 400 (n=386) asymptomatic pregnant patients, with a positive rate of three percent (3.1%).

During this pandemic, PROGyn has taken on the task of educating, dissipating disinformation, and defending the rights of future mothers through responsible use of social media and interaction with multiple academic and professional stakeholders and leaders. And we hope this viral disease can be better monitored, and that it does not cause harm to our pregnant and unborn babies. But for now, through these surveillance efforts, we will try to identify concerning findings among pregnant mothers. In addition, as a SENTINEL group, obstetrical patients could provide indirect documentation on the behavior of this virus in the asymptomatic population.

Puerto Rico’s obstetricians are ready once again to collaborate with the Department of Health to protect their patients as it was done during the Zika epidemic. We recognize these are ambitious public health goals, which require everyone to be consistent in data collection, centralization, and analysis. Yet, with the cooperation of all the entities described here, we expect to generate a SARS-Cov-2 monitoring system that is effective today, while being able to provide future detection of new outbreaks. CASSS aims to improve the care of pregnant patients, while seeking to establish a SENTINEL group that will provide information about this pandemic in Puerto Rico. The implementation of an effective vaccination program may take time, and supporting SENTINEL surveillance may be part of the solution to track and control COVID-19 locally and perhaps also in other states and jurisdictions.

Dr. Nabal Bracero is the president and founder of nonprofit organization Puerto Rico Obstetrics and Gynecology (PROGyn); chairman of the American College of Obstetricians and Gynecologists (ACOG) – Puerto Rico Section; and elected treasurer of ACOG District IV .

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