INTRODUCTION Polyserositis is described as inflammation with effusion of more than one serous membrane. There is very little published literature linking it to COVID-19 as a late complication.

OBJECTIVES Present and describe a case of post–COVID-19 polyserositis.

METHODS Data were collected from the medical record of a female patient admitted for fainting spells and marked weakness. The patient underwent a clinical evaluation, additional hematology, imaging and histopathology tests, and a surgical procedure.

The new index, called the abdominal adipose deposit index, was obtained by multiplying the subcutaneous fat thickness by visceral fat thickness, both measured by ultrasound. A cutoff point was established that facilitated discernment of an unhealthy phenotype: normal weight but metabolically obese, a cardiometabolic risk factor.

RESULTS We present the case of a 57-year-old female patient admitted to hospital for fainting spells and marked weakness, four months after COVID-19 infection. She also had a history of obesity, asthma, type 2 diabetes mellitus and a cholecystectomy in December 1992 for gallstones. Clinical assessment revealed pericardial effusion and bilateral pleural effusion, in addition to a tumor-like lesion outside the pericardium, proximal to the right ventricular wall. A surgical procedure and findings from additional tests led to diagnoses of thymic remnants and polyserositis.

CONCLUSIONS This is a case of polyserositis in a post–COVID-19 patient. After other causes of polyserositis were ruled out, and since there is a likely physiological and pathogenic mechanism operating between the two diseases, the polyserositis was determined to be a late complication of COVID-19. To date, it is the second case reported in the world and the first reported in Cuba.

KEYWORDS COVID-19, SARS-CoV-2, colchicine, pericardial effusion, pleural effusion, pericarditis, thoracoscopy, Cuba

Globally, SARS CoV-2 omicron variant has led to a notable increase of COVID-19 diagnoses, although with less severe clinical manifestations and decreased hospitalizations. The omicron wave swelled faster than previous waves, completely displacing the delta variant within weeks, and creating worldwide concern about final, successful pandemic control. Some authors contend that symptoms associated to omicron differ from ‘traditional’ symptoms and more closely resemble those of the common cold.

One major COVID-19 symptom frequent with other variants—loss of taste and smell—is rarely present with omicron. This may be of interest, since it has also been suggested that direct SARS-CoV-2 invasion into the brainstem through the olfactory nerves by transsynaptic pathways could provide one explanation for the acute respiratory distress syndrome refractory to treatment. Brainstem infection by SARS-CoV-2 can severely damage the respiratory center, triggering functional deviations that affect involuntary respiration, leading to acute respiratory distress syndrome refractory to treatment, the main cause of death in COVID-19 patients. A shift in the omicron SARS-CoV-2 entry pathway from cell-surface fusion, triggered by TMPRSS2, to cathepsin-dependent fusion within the endosome, may affect transmission, cellular tropism and pathogenesis. Therefore, we can hypothesize that this entrance modification may impact transmission from the olfactory nerve to the brainstem through transsynaptic pathways. A decrement of the virus’s direct invasion into the brainstem could diminish respiratory center dysfunction, reducing acute respiratory distress syndrome and the need for mechanical ventilation.

KEYWORDS SARS-CoV-2, COVID-19, olfactory nerve, COVID-19 pandemics, respiratory center, smell, anosmia, taste, ageusia, brain stem, cathepsins, endosomes

INTRODUCTION Bile acids are signaling molecules with immune, metabolic and intestinal microbiota control actions. In high serum concentrations they increase inflammatory response from the liver-gut axis, until causing multiorgan failure and death; therefore, they may be associated with COVID-19’s clinical progression, as a consequence of tissue and metabolic damage caused by SARS-CoV-2. While this topic is of considerable clinical interest, to our knowledge, it has not been studied in Cuba.

OBJECTIVES Study and preliminarily characterize patients admitted with a diagnosis of COVID-19 and high levels of serum bile acids.

METHODS A preliminary exploratory study was carried out with descriptive statistical techniques in 28 COVID-19 patients (17 women, 11 men; aged 19–92 years) who exhibited high levels of serum bile acids (≥10.1 µmol/L) on admission to the Dr. Luis Díaz Soto Central Military Hospital in Havana, Cuba, from September through November 2021.

RESULTS On admission patients presented hypocholesterolemia (13/28; 46.4%), hyperglycemia (12/28; 43.0%) and hyper gamma-glutamyl transpeptidase (23/28; 84.2%). Median blood glucose (5.8 mmol/L) and cholesterol (4.1 mmol/L) were within normal ranges (3.2‒6.2 mmol/L and 3.9‒5.2 mmol/L, respectively). Severe or critical stage was the most frequent (13/28) and median serum bile acids (31.6 µmol/L) and gamma-glutamyl transferase (108.6 U/L) averaged well above their respective normal ranges (serum bile acids: 0‒10 µmol/L; GGT: 9‒36 U/L). Arterial hypertension was the most frequent comorbidity (19/28; 67.9%).

CONCLUSIONS Severe or critical stage predominated, with serum bile acids and gamma-glutamyl transferase blood levels above normal ranges. The study suggests that serum bile acid is toxic at levels ≥10.1 µmol/L, and at such levels is involved in the inflammatory process and in progression to severe and critical clinical stages of the disease. In turn, this indicates the importance of monitoring bile acid homeostasis in hospitalized COVID-19 patients and including control of its toxicity in treatment protocols.

KEYWORDS COVID-19, SARS-CoV-2, bile acids and salts, gamma-glutamyl transferase, pregnant women, postpartum, Cuba

The COVID-19 pandemic has caused notable changes in all areas of our lives. Pandemic-coping strategies include attention and care at various levels, for different people and in various scenarios. Death is one of the most feared consequences of COVID-19 for both patients and their families; for the latter, the grief and adaptation processes to loss require that care for grievers be an important part of the public health response to the COVID-19 pandemic.

Grief from losses due to COVID-19 has distinctive features: it is not anticipatory (with virtually no time or progressive stages to facilitate adaptation to loss); closure or goodbyes are not possible (in-person social support decreases due to distancing to minimize risk of infection); it may affect various close relationships (a relevant predictor of complicated grief); it may imply stigmatization by peers, friends and neighbors; it is preceded by a period of absence of fluid and in-person communication between family members and the hospitalized patient; and those who break the news of the death are often professionals in red zones who are stressed and do not always have the skills or the ability to properly communicate bad news.

The death of a family member from COVID-19 generally causes an unexpected crisis in the family, which is already affected by the pandemic and its daily consequences. This has prompted an analysis of COVID-19 loss on family life and how best to mitigate its consequences.

During the COVID-19 pandemic, care and monitoring of the grief of family members and those who were close to the deceased require psychological action within a framework of comprehensive care, which demands preparation of healthcare professionals. Experiences described are taken from some actions developed in Cuba.

KEYWORDS Grief, psychology, death, attitude to death, COVID-19, SARS-CoV-2, Cuba

INTRODUCTION The use of various diagnostic techniques is increasingly common in pandemic scenarios. It is important to update evaluations of their metric properties in different times and settings.

OBJECTIVE Evaluate metric properties of a SARS-CoV-2 rapid antigen test relative to a reference standard.

METHODS We carried out a prospective evaluation study of the SARS-CoV-2 rapid antigen test as compared to the RT-PCR test, which is considered the reference standard. Our sample was comprised of 778 individuals, and we calculated sensitivity, specificity, predictive values, prevalence and validity indices.

RESULTS Of the total 778 samples, 70 were true positives, 658 were true negatives, and 27 were false negatives when compared to RT-PCR test results. We obtained a sensitivity of 75.3% (95% CI = 65.96–84.50); a specificity of 96.1% (95% CI = 94.53–97.59); 72.2% for positive predictive value, and 96.6% for negative predictive value. The estimated prevalence was 11.9% and the validity index was 93.6%.

CONCLUSIONS The index values validate use of the SARS- CoV-2 rapid antigen test until prevalence falls below 2.5%, since as SARS-CoV-2 infection prevalence decreases, so does the predictive value of the PCR result.

The use of the SARS-CoV-2 rapid antigen test on the Isle of Youth, Cuba, was decisive in the pandemic’s clinical– epidemiological management.

KEYWORDS SARS-CoV-2, COVID-19, antigens, validation study, sensitivity and specificity, Cuba

INTRODUCTION COVID-19 sequelae, or the short-, medium-, and long-term manifestations of the disease are under continuous study. There are currently few reports on the evolution of hematological variables following a demonstrated absence of SARS-CoV-2 after infection.

OBJECTIVE Identify hematological alterations in Cuban adults recovered from SARS-CoV-2 infection, and their relation with disease severity.

METHODS We selected 348 persons recovered from COVID-19 residing in Havana, Cuba with an RT-PCR study negative for SARS-CoV-2 performed two weeks after hospital discharge; a structured survey was administered to obtain clinical–epidemiological data. Three groups were established according to COVID-19 clinical criteria: asymptomatic, mild/moderately symptomatic, and severely symptomatic, which, in turn, were divided according to hospital discharge date and blood sample collection date. We performed hemograms with differential leukocyte counts and compared results among groups. We then measured the associations between hematological variables, personal medical history, and relevant lifestyle habits (smoking).

RESULTS All hematological variables were within normal reference limits, although men from the group of severely ill patients had increased total leukocytes, neutrophils and lymphocytes, and decreased hemoglobin and eosinophils, which was also evident in those with a recovery time of 31–90 days.

CONCLUSIONS The relation between hematological variables and degree of clinical severity offers evidence as to persistence of systemic alterations (possibly inflammatory) associated with viral infection. Their identification and characterization can facilitate personalized patient followup and rehabilitation.

KEYWORDS COVID-19, SARS-CoV-2, hematology, leukocytosis, neutrophils, eosinophils, Cuba

Cuba’s decision in September 2021 to launch a massive vaccination campaign against COVID-19 for children as young as two years old turned heads around the world—of clinicians, immunologists, public health experts, governments and regulatory authorities alike. Since then—and just as pediatric COVID-19 hospitalizations reached record numbers globally—some two million Cuban children and adolescents have received the Cuban Soberana vaccines (1.7 million, or 81.3% of that population through December 16, 2021).[1]

Why did Cuban health authorities decide to vaccinate children? What clinical trials provided the evidence for such a course of action, especially for the youngest? And what have been the results thus far?

To answer these and other questions, MEDICC Review spoke with Dr Rinaldo Puga, principal investigator for the completed phase 1/2 clinical trials of the Finlay Vaccine Institute’s Soberana 02 and Soberana Plus vaccines in pediatric ages. Dr Puga’s 30 years as a practicing pediatrician have been accompanied by teaching and research, the latter earning him awards from the Cuban Academy of Sciences, among others. He is currently chief of pediatrics and chair of the Scientific Council at the Cira García Clinic in Havana, which granted him leave to lead the pediatric vaccine trials.

As 2021 drew to a close, Cuba struggled to contain the highly transmissible omicron variant of SARS-CoV-2, braced for a new wave of infections and kept a close eye on other variants of concern popping up around the world—a common experience to countries everywhere as we head into the second year of the pandemic. In Cuba, however, there is one marked difference making all the difference: by early January, 87% of the population was fully vaccinated using a three-dose schedule of vaccines developed and produced on the island.[1] This massive vaccination campaign is complemented by a rapid booster rollout—also using Cuban vaccines—that began in December 2021 and was ongoing as we finalized this issue.

The island nation was able to achieve the third highest COVID-19 vaccination rate in the world[2] after decades of scientific investment, research, discovery and innovation; regulatory oversight and compliance; professional training; and increased production capacity. But a vaccine is only as effective as the health system charged with administering it—in a safe and timely manner, to as many people as possible. Here too, Cuba has decades of experience, including a national pediatric immunization program where 98% of children under 5 are immunized against 13 diseases,[3] an annual polio vaccination campaign (both launched in 1962 and uninterrupted since) and campaigns to contain epidemics such as H1N1.

When the first COVID-19 cases were detected on the island in March 2020, Cuba harnessed this vaccine experience, making a hard tack towards developing its own vaccines. Two of the main protagonists in the country’s biotechnology development, the Finlay Vaccine Institute (IFV) and the Genetic Engineering and Biotechnology Center (CIGB), both with several groundbreaking preventive and therapeutic vaccines in their portfolios, led the search for a vaccine. Today, Cuba has three vaccines authorized for emergency use—Soberana 02 and Soberana Plus developed by IFV, and Abdala, developed by CIGB. Schedules with these vaccines have demonstrated more than 90% efficacy in clinical trials,[4] and after regulatory approval for emergency use, became the backbone of Cuban COVID-19 vaccination efforts. A fourth vaccine, Mambisa (CIGB), administered nasally, and a fifth, Soberana 01 (IFV) are still in clinical trials.

For this installment in MEDICC Review’s series spotlighting leading women of Cuban science, we sat down with Dr Verena Muzio, Director of Clinical Research at CIGB. A pioneer of Cuba’s biotechnology sector, she is an immunologist with a doctorate in biological sciences. Her professional trajectory began researching the genetically engineered hepatitis B surface antigen that led to the development of Cuba’s recombinant hepatitis B vaccine in 1989. The same technological platform used in this vaccine was used to develop CIGB’s Abdala vaccine against SARS-CoV-2—part of the reason Cuba was able to secure a vaccine so quickly. A phase 3 clinical trial determined a 92.28% efficacy rate for Abdala, with results to appear in forthcoming publications.

INTRODUCTION The percentage of asymptomatic COVID-19 cases worldwide is estimated at 18–50%; 53% in Cuba specifically, and 58% in Havana, the Cuban capital and the 2020 epicenter of the country’s COVID-19 epidemic. These figures, however, do not represent the transmission capacity or behavior of asymptomatic cases. Understanding asymptomatic transmission’s contribution to SARS-CoV-2 spread is of great importance to disease control and prevention.

OBJECTIVE Identify the epidemiological implications of asymptomatic SARS-CoV-2 infection in Havana, Cuba, during the first wave of the epidemic in 2020.

METHODS We carried out a cross-sectional study of all confirmed COVID-19 cases diagnosed in Havana, Cuba, from March 16 through June 30, 2020. The information was obtained through review of the standardized form for investigation of suspected and confirmed cases. Examined variables included age, sex, occupation, case type and source of infection. Cases were divided into asymptomatic and symptomatic groups, and transmission was characterized through the creation of a contact matrix. Analysis was carried out in Epidat and R.

RESULTS We studied 1287 confirmed cases, of which 57.7% (743) were asymptomatic, and 42.3% (544) were symptomatic. Symptomatic presentation was the most common for both imported and introduced cases, while asymptomatic presentation was more common in autochthonic cases and infections from an undetermined source. Asymptomatic infection was more common in groups aged <20 and 20–59 years, while symptomatic infection was more common in those aged >60 years. In the contact matrix, 34.6% of cases (445/1287) were not tied to other cases, and 65.4% (842/1287) were infectious–infected dyads, with symptomatic–symptomatic being the most common combination. The majority of primary cases (78.5%; 1002/1276) did not generate secondary cases, and 85.6% (658/743) of asymptomatic cases did not lead to other cases (although one asymptomatic superspreader led to 90 cases in a single event). However, 63.2% (344/544) of symptomatic primary cases generated secondary cases, and 11 symptomatic superspreaders spawned 100 secondary cases in different events.

CONCLUSIONS Asymptomatic SARS-CoV-2 infection was the most common form of COVID-19 in Havana during the study period, but its capacity for contagion was lower than that of symptomatic individuals. Superspreader events under specific conditions played an important role in sustaining the epidemic.

KEYWORDS COVID-19, SARS-CoV-2, pandemics, asymptomatic infection, Cuba