Lack of vaccination and associated comorbidities predispose to the need for intensive care in individuals infected with the delta variant - A case cohort study from a tertiary care hospital in New Delhi, India.

Dear Editor,

The COVID-19 pandemic has witnessed its worst period during the 2nd wave in India. More than 4,00,000 new cases and 4000 deaths were recorded at its peak [1]. It is recognized that those who require admission to the Intensive Care Units (ICU) have poor prognosis. Several risk factors are known to increase the severity of disease [2]. There has been growing interest in the SARS-COV-2 Variant of Interest (VOI) and Variant of Concern (VOC). These VOC are highly transmissible, cause severe disease, and has the ability to bypass the host immunity [3]. The Delta variant (B.1.617.2) has recently spread to more than 85 countries and has taken over all the other variants. It was found responsible for India's 2nd and the 3rd wave of the UK [4].

We did an observational study of our ICU admitted cases in two months of the 2nd COVID wave (in April and May 2021). The Genome Sequence analysis of 82 positive nasopharyngeal RT-PCR samples (reported at our hospital) was performed at the National Centre for Disease Control, Delhi.

There were 51 males and 31 females in this cohort. The majority of them (76.83%) were above the age of 50 years. The most common associated medical comorbidities were hypertension (41.46%) and diabetes mellitus (39.48%). The majority (76.83%) of these cases were non-vaccinated, and 23.17% had taken a single vaccine dose and none had received two vaccine doses. We found the Delta variant (B.1.617.2) was the most common and predominant lineage of SARS-COV-2 (97.12%) responsible for the severe disease in these cases (Fig. 1 ).

Fig. 1

Lineage of SARS-CoV-2 found in ICU patients.

Several comorbidities like cancer, chronic kidney and lung diseases, diabetes mellitus, hypertension, obesity, and immune-compromised states are associated with severe disease and increased mortality [2]. The Delta variant is now the leading variant globally, carries a higher risk of household transmission by 60%, compared to the Alpha variants and is also responsible for a higher number of hospital and ICU admissions. The CT value (cycle threshold) is lower in people infected with it, meaning that they contain more viruses and can spread these quickly. It is also recognized that this VOC can easily infect the cells of human airways and can infect people even after a lower exposure [5].

From this observational study, it can be derived that the lack of vaccination and associated comorbidities predispose to the need for intensive care in individuals infected with the delta variants, especially after the age of 50 years.

Disclosure

We do not have anything to disclose commercial or similar relationships to any products or companies.

Funding

None.

Declaration of competing interest

All the four authors confirm that we have no Conflict of Interest to disclose.