The COVID-19 pandemic exhibits different characteristics in each country, related to the extent of SARS-CoV-2 local transmission, as well as the speed and effectiveness of epidemic response implemented by authorities. This study presents a descriptive epidemiological analysis of the daily and cumulative incidence of confirmed cases and deaths in Cuba from COVID-19 in the first 110 days after first-case confirmation on March 11, 2020. During this period, 2340 cases (20.7 x 100,000 population) were confirmed, of which 86 patients died (case fatality 3.67%; 52 men and 34 women). Mean age of the deceased was 73.6 years (with a minimum of 35 years and a maximum of 101), with the average age of men lower than that of women. More than 70% of all deceased had associated noncommunicable diseases. The incidence curve ascended for five weeks and then descended steadily. The average number of confirmed cases and deaths for the last week included (June 23–28, 2020) were 25 and 1 respectively; the curve always moved within the most favorable forecast zone of available mathematical models and the effective reproductive number fell below 1 after the fifth week following the onset of the epidemic.

We present the prevention and control measures implemented during this period—some unique to Cuba—and assess their effectiveness using two analytical tools: comparison of observed deaths and confirmed cases with those predicted by mathematical models; and estimation of the effective reproductive rate of SARS-CoV-2. Some distinctive features of this strategy include nationwide door-to-door active screening for individuals with fever and/or symptoms of respiratory distress, isolation of cases and quarantine of contacts of confirmed cases and of persons suspected of having the virus. During this period, Cuba’s response to the epidemic was successful in flattening the curve and limiting transmission, resulting in fewer cases and a lower number of subsequent deaths.

KEYWORDS COVID-19, SARS-CoV-2, epidemiology, pandemic, emerging infectious disease, contact tracing, patient isolation, Cuba

BACKGROUND The novel coronavirus SARS-CoV-2 is responsible for the current global pandemic. There is a concerted effort within the global scientific community to identify (and thereby potentially mitigate) the possible modes of transmission through which the virus spreads throughout populations.

OBJECTIVE Summarize the ways in which SARS-CoV-2 is transmitted and provide scientific support for the prevention and control of COVID-19.

EVIDENCE AQUISITION We conducted an extensive literature search using electronic databases for scientifi c articles addressing SARSCoV-2 transmission published from December 28, 2019 through July 31, 2020. We retrieved 805 articles, but only 302 were included and discussed in this review. The report captured relevant studies investigating three main areas: 1) viral survival, 2) transmission period and transmissibility, and 3) routes of viral spread.

DEVELOPMENT Currently available evidence indicates that SARSCoV-2 seems to have variable stability in different environments and is very sensitive to oxidants, such as chlorine. Temperature and humidity are important factors influencing viral survival and transmission. SARSCoV-2 may be transmitted from person to person through several different routes. The basic mechanisms of SARS-CoV-2 transmission person-to-person contact through respiratory droplets, or via indirect contact. Aerosolized transmission is likely the dominant route for the spread of SARS-CoV-2, particularly in healthcare facilities. Although SARS-CoV-2 has been detected in non-respiratory specimens, including stool, blood and breast milk, their role in transmission remains uncertain. A complicating factor in disease control is viral transmission by asymptomatic individuals and through what would otherwise be understood as innocuous human activities.

CONCLUSIONS This article provides a review of the published research regarding human-to-human transmission of SARS-CoV-2 and insights into developing effective control strategies to stop viral propagation.

KEYWORDS COVID-19, SARS-CoV-2, transmission, pandemics, microbial viability

INTRODUCTION On March 11, 2020, WHO declared COVID-19 a pandemic and called on governments to impose drastic measures to fight it. It is vitally important for government health authorities and leaders to have reliable estimates of infected cases and deaths in order to apply the necessary measures with the resources at their disposal.

OBJECTIVE Test the validity of the logistic regression and Gompertz curve to forecast peaks of confirmed cases and deaths in Cuba, as well as total number of cases.

METHODS An inferential, predictive study was conducted using logistic and Gompertz growth curves, adjusted with the least squares method and informatics tools for analysis and prediction of growth in COVID-19 cases and deaths. Italy and Spain—countries that have passed the initial peak of infection rates—were studied, and it was inferred from the results of these countries that their models were applicable to Cuba. This hypothesis was tested by applying goodness-of-fit and significance tests on its parameters.

RESULTS Both models showed good fit, low mean square errors, and all parameters were highly significant.

CONCLUSIONS The validity of models was confirmed based on logistic regression and the Gompertz curve to forecast the dates of peak infections and deaths, as well as total number of cases in Cuba.

KEYWORDS COVID-19, SARS-CoV-2, logistic models, pandemic, mortality, Cuba

This MEDICC Review roundtable brings you specialists from Havana’s Pedro Kourí Tropical Medicine Institute (IPK), who are working directly with testing, research and patient care during the COVID-19 pandemic. Founded in 1937 by its namesake, the Institute has gained considerable worldwide prestige. Today, it is a PAHO–WHO Collaborating Center for the Study of Dengue and Its Vector, and for the Elimination of Tuberculosis. Its main role within Cuba’s health system is as the national reference center for prevention, control, management and elimination of infectious diseases, including epidemics. Its 479 workers staff 32 departments, including laboratories, research and teaching facilities, a hospital and isolation center. The IPK’s hospital treats later-stage AIDS patients, while the Institute is the national reference center for attention to all HIV-positive patients and maintains the national HIV/AIDS registry, as well as registries for other infectious diseases. The institution was responsible for training the Cuban doctors who served in West Africa during the 2014–2016 Ebola outbreaks and for those going abroad to assist in the COVID-19 response today, and its professionals offer an internationally-recognized biennial course on dengue.

Introducing our readers to roundtable participants (in order of appearance):

Manuel Romero-Placeres MD MPH PhD is a physician with dual specialties in family medicine and epidemiology, as well as a degree in public administration and a doctorate in medical sciences. He also holds a master’s degree in public health, concentrating on environmental health. He is full professor and senior researcher at the Medical University of Havana, and is a member of the Cuban Academy of Sciences. Dr Romero is director of the Pedro Kourí Tropical Medicine Institute (IPK).

Daniel González-Rubio MD MS PhD is an internist with a master’s degree in infectology and tropical diseases, and a doctorate in medical sciences. He is full professor and associate researcher at the Medical University of Havana and chief of the Tropical Medicine Unit at IPK.

Sonia Resik-Aguirre MD MS PhD is a physician specializing in microbiology with a master’s degree in virology and a doctorate in medical sciences. She is full professor and senior researcher at the Medical University of Havana. Dr Resik heads the Virology Department and directs the National Polio Reference Laboratory at IPK. She has participated in numerous international collaborations, including 12 with WHO on inactivated polio vaccine. She is a member of WHO’s SAGE Polio Working Group.

This MEDICC Review roundtable gathers some of Cuba’s top researchers in the fields of vaccines and biotechnology, all of whom work in institutions belonging to BioCubaFarma, the umbrella company of Cuban biotech and pharmaceutical R&D, production, distribution and export. Founded in 2012, the company is comprised of 34 enterprises with 61 lines of production and […]

The main characteristics and challenging symptoms of COVID-19, caused by the novel coronavirus SARS-CoV-2, are related to respiratory distress. Although most patients have mild symptoms such as fever, headache, cough, myalgia and anosmia, some develop acute respiratory distress syndrome, leading to death in many cases. Human coronavirus (CoVs) were responsible for two previous worldwide outbreaks: […]