COVID-19 and dengue coinfection in Veracruz, Mexico

Dear editor:

Veracruz, a state in southeastern Mexico characterized by being an endemic area for arboviruses such as Dengue, Zika and Chikungunya [1], during the current pandemic the presence of co-infections with the Sars Cov2 virus was inevitable, identifying 14 cases in 2020, highlighting the presence of classic symptoms of dengue (fever, myoarthralgia and headache) as well as of COVID-19 (cough and dyspnea), the hematological alterations were dominated by dengue, characterized by leukopenia, lymphopenia and thrombocytopenia, likewise the serological and molecular diagnoses were clear for both entities; the radiological manifestations were dominated by COVID-19 with the presence of even extensive subpleural infiltrates classified as CORADS 5 and 6 in most cases. However, all patients, some with significant comorbidities, had a benign course and all had a good outcome and prognosis. Table 1 .

Table 1.

Characteristics of Dengue-COVID-19 coinfection cases

	N = 14
Average age	46 years
Genre	Men (71%)
Comorbidities	Diabetes 2
	Renal disease 1
	Lupus 1
	Ethylism 1
	Allergies 1
Symptoms	Fever 100%
	Myoarthralgia 100%
	Cough 80%
	Headache 80%
	Dyspnoea 70%
Biochemical alterations	Leukopenia 100%
	Lymphopenia 100%
	Thrombocytopenia 90%
Biochemical diagnosis COVID-19	RT-PCR 64%
	IgM/IgG 21%
	Not done 15%
Tomographic diagnosis COVID-19	CORADS 6 72%
	CORADS 5 14%
	Not done 14%
Biochemical diagnosis Dengue	NS1 93%
	IgM/IgG 57%
	RT-PCR 14%
Prognosis	Good (100%)
ICU or Mechanic ventilation	0%

Both Dengue and COVID-19 share the pathophysiology in terms of the presence of plasma leakage, coagulopathy and thrombocytopenia, mainly severe dengue, due to the induction of proinflammatory cytokines such as IL-6 and TNF by the viral action of both denguevirus and Sars Cov2, which could translate severe pictures with cytokine storm and poor outcomes in these patients. In this area, cases of coinfection with more severe conditions have been reported that require a stay in intensive care units and even lead to death. A recent systematic review demonstrated serious and fatal cases with COVID-19 and Dengue coinfection, with cases reported in South America, Europe, and Asia [[2], [3], [4]].

There are some concepts that could explain that milder or more severe symptoms may occur in these coinfections, some are: coinfection by COVID-19 and Dengue presents less severe symptoms compared to isolated monoinfection, probably associated with opposite pro and anticoagulant states triggered by SARS-CoV-2 and Denguevirus respectively. In addition, the possible improvement of Dengue has been considered when there is a second infection with different viruses, including Sars Cov2 [5,6].

However, on the other hand, it is commented that there are some phenomena such as seasonal decreases in one virus when another predominates (COVID-19 predominating over dengue in pandemic waves) and the so-called viral interference phenomenon, in which a virus blocks the entry the other by inhibitory competition on target cells [7].

Finally, the presence of this co-infection will have prior serological determinants (including false positives due to cross-reactivity, the ideal being determination by RT-PCR), virological and interactions between viruses, seasonal phenomena favored in turn by other issues such as human migration, vectors competent in the area and the burden of the disease at that time, which will end up favoring COVID-19 and Dengue coinfection.