The endemic curve of average annual morbidity and mortality rates for VH shows an overall endemic-epidemic behaviour with epidemic waves of morbidity preceding mortality in the period from 1999 to 2016. Subsequently, both rates seem to fall progressively, being more important in mortality rates. Morbidity explains, in acute infectious pathologies, mortality trends, as occurs in the endemic VH curve, a proportion of which is acute, which may impact on sequencing [21].
Epidemic behaviour of VHA and UVH match with the large troughs and landslides caused by torrential rains that occurred during those years in several regions and localities of the country. The activity of tropical storm Bret in 1993 caused floods and material losses through Venezuelan territory, including the Monagas, Sucre, Nueva Esparta, Distrito Federal, Aragua, and Carabobo states, among others, and it is estimated that at least 120 people died, several and more than 4,000 victims as a result of tropical storm Bret [22]. Other catastrophes such as the one that occurred in Vargas state in 1999 and 2005, which destroyed housing and sanitation infrastructure, including the collapse of sewage and water systems, mainly in the Vargas, Miranda, and Falcón states [9]. Similarly, in 2005, in the Mocotíes tragedy in Mérida state, land communications were interrupted, among other natural disasters caused by rain in Aragua and Miranda states, with deaths and great destruction of populations such as Araira, with many refugees [10].
The vaccine has had a significant effect in reducing HAV infections, although coverage rates remain lower compared to other childhood vaccines. In the United States, around 87% for the first dose and 57% for the second dose, long-term immune response up to age 40 years was observed in more than 90% of patients who received both doses of the two-vaccine series [23]. Countries in the region, such as Argentina, have had successful experiences following the incorporation of the vaccine into the national immunisation schedule, with rates declining sharply from 113.3/100,000 in 2004 to 1.4/100,000 in 2011. Throughout this period, vaccination coverage was over 90% nationwide [24]. In contrast, in Venezuela, in the case of hepatitis A vaccination, it is not included in the Venezuelan Expanded Programme on Immunisation, it is only applied in the private sub-sector and in the years of better economic boom, prior to 2013, it reached between 10% and 15% of vaccination coverage, according to personal and press reports. However, there is no reliable data regarding private sector indicators on vaccination [25]. Finally, the WHO Global Health Observatory [26] shows the most relevant indicators for monitoring VH, such as VHB and VHC, from 2000 to 2020; however, it does not keep records of VHA, morbidity data or VH seroprevalence, which further limits understanding of what is happening in Venezuela.
Chronic HBV infection occurs in approximately 5% of those infected in adulthood, compared to 90% of those infected in early childhood [27, 28]. Therefore, the global incidence of chronic HBV infection is largely due to vertical, mother-to-child, and early childhood transmission, and this is the focus of the WHO elimination plan. The primary intervention is therefore vaccination. However, vaccination coverage rates have been declining [11], including hepatitis B vaccination, which may partly explain the endemic behaviour of this infection in the country [29]. This study found a negative correlation between VHB and VH mortality and chronic VH sequelae; that is, as VHB deaths increase, deaths from sequelae decrease. A study involving 116 (61.3 ± 12 years) patients diagnosed with hepatocellular carcinoma seen in two medical centres in Caracas documented that the aetiology was HBV in 14.7% of cases and that it was also diagnosed more frequently in patients with HBV cirrhosis [30]. According mortality yearbooks, the majority of deaths (90%) by malignant tumour of the liver and intrahepatic bile ducts, non-alcoholic liver fibrosis, and cirrhosis occur in adults older than 44 years, coinciding with the most frequent age group (older than 35 years) where the majority of deaths due to sequelae of VH are found (> 96%), suggesting that they are a result of chronic hepatitis.
The prevalence of HCV infection varies according to geographical area and different risk groups [31]. In Venezuela, there are few studies aimed at determining the frequency of HCV infection in the general population. However, prevalence of HCV infection have been reported from 0.6–2.1% [31, 32]. Most seroprevalence studies in the country have focused mainly on small regions (mainly the city of Maracaibo in the northwest of the country), Amerindians and high-risk groups such as sex workers, haemodialysis patients, and prisoners, with prevalence ranging from 0–71% [14, 33–41], with the expected trend of increasing prevalence of HCV infection exposure as a function of age. In addition, studies in Latin America and the Caribbean have reported several other risk factors for HCV infection and eventual hepatocellular carcinoma in these high-risk groups [42–44]. HCV was the aetiology in one third of 116 Venezuelan patients diagnosed with hepatocarcinoma [30]; however, information on HCV-related sequelae in Venezuela remains very limited.
The limitations of this study are several: (1) the unavailability of bulletin publications after 2016 prevent in country morbidity and mortality analysis from being more up-to-date; (2) data quality limits the certainty of our results, although the bulletins are guided by the ICD-10, reporting is done by professionals from all over the country, in different socio-economic contexts, which probably limited the molecular confirmation of VH; (3) uncertainty about the size of the populations, the denominators of rates that are extrapolated from a census of several years’ duration and during a political and economic crisis of great dimensions that has generated significant migration of Venezuelans, many of them of productive age, with an important impact on the size of the general population. It is estimated that there has been a slow migration since 2000, which intensified in the last 10 years [45]. Finally, the information available on VHD and VHE in the bulletins is null and void, which is why they could not be analysed in this time series. Despite these limitations, the trends in morbidity and mortality behaviour provided by the Venezuela’s Ministry of Health offer a better understanding of the behaviour of VH in the country in order to guide effective responses to this important public health problem.