Impact of COVID-19 lockdown during 2020 on the occurrence of vector-borne diseases in India.

Abstract

India imposed one of the world's largest nationwide lockdown in the aftermath of COVID-19 pandemic in March 2020 which was partly extended up to December. Some of the impacts of the COVID-19 lockdown on the economy, research, travel, education, and sports were readily apparent; the same was less obvious in the occurrence of vector-borne diseases (VBDs). The objective of this study was to statistically determine the impact of the COVID-19 lockdown on the occurrence of VBDs in India. The reported incidence of VBDs such as malaria, dengue, Chikungunya, Japanese encephalitis, and kala-azar in India during the years 2015-2019 was analyzed by fitting Poisson and negative binomial (NB) models for each VBDs separately. The number of cases reported was compared with the number of cases predicted for each year from 2015 to 2020 for all the VBDs under study to infer whether or not the lockdown had any impact on their prevalence in India. The percentage of the actual case was lower by 46, 75, 49, 72, and 38 respectively for malaria, dengue, Chikungunya, Japanese encephalitis, and kala-azar when comparing the lockdown period and the year before lockdown (2020 vs. 2019). The number of cases predicted for the year 2020 based on the trend of the five preceding years (2015-2019) also showed a great variation between actual and predicted cases. The differences in cases were considered as the cases missed in 2020 were largely due to the lockdown. The analysis showed that the lockdown had a considerable impact on the occurrence of VBDs.