Monsoon, Vitamin-D, COVID-19: Implications for India

COVID-19, caused by SARS-CoV-2 virus has caused 11,903 deaths in India as of 17 June 20201. Epidemiological evidence shows that transmission and peaks of infectious diseases are associated with the timing and severity of monsoon, generally peaking towards the end of the monsoon period2,3. Observational studies indicate that vitamin D deficiency might be a risk factor for severity and mortality of COVID-194–6. This blog reviews the public health consequences in India due to COVID-19 during monsoon, keeping into account emerging evidence of the possible role of vitamin D in COVID-19 severity, lifting of the lockdown and the pressure on the healthcare system due to other infectious diseases during monsoon.

Potential Impact of Monsoon on SARS-CoV-2 Transmission & Immunity
Studies indicate that even in a sunnier country like India, vitamin D deficiency prevails in epidemic proportions due to reduced exposure of skin, dietary habits such as vegetarianism as well as limited fortification of food7. Skin synthesis via exposure to solar Ultraviolet-B (UVB) radiation is considered as the significant source of vitamin D as dietary intake is generally insufficient8. Government of India initiated a lockdown limiting the movement of 1.3 billion people from 24 March 2020 until 31 May 2020 in 4 phases (58 days) and has gradually started lifting the lockdown in a phased manner from 01 June, though COVID-19 deaths are increasing9. Lockdown, although helped in reducing the transmission of SARS-CoV-2, might have led to limited sun exposure leading to an increased likelihood of vitamin D deficiency in the general population.
Furthermore, the lifting of lockdown coincides with the onset of the monsoon, when the likelihood of UVB Radiation exposure is limited primarily due to lower sunshine hours, thick cloud cover and limited outdoor activities. Lifting of lockdown during monsoon may also lead to an increased viral transmission as people are more likely to stay indoors with lower ventilation as evidenced by the surge in the COVID-19 deaths9.
Other Impact of Monsoon on Healthcare System
Prior studies indicate that influenza tends to peak during the monsoon months, i.e., July-September in significant parts of India coinciding with the timing of monsoon period10. Heavy rainfall and flooding, which is prevalent in monsoon, can create conditions conducive for other infectious disease outbreaks such as – dengue, malaria, influenza, diarrhoea, cholera and other respiratory diseases11. Simultaneous contraction of COVID-19 and these infectious diseases prevalent during monsoon may also lead to poor clinical outcomes for COVID-19 patients.
Cities like Mumbai is prone to yearly monsoon flooding, causing disruptions in traffic – severely limiting the transportation of patients needing critical care to the hospitals. Furthermore, the sudden increase of such infectious diseases during monsoon is also likely to cause strain in the healthcare system, limiting the hospital capacity available for COVID-19 patients and vice versa. Heavy rainfall may also limit the governmental response to set up additional critical care capacity. These factors may further limit the healthcare system’s ability to provide critical care to COVID-19 patients.

Need for Measures in India
Healthcare providers should expect an increase in cases of COVID-19 as well as other infectious diseases and prepare for an increase in hospital capacity. Further, healthcare practitioners might need to consider factors such as diet, sunlight exposure and consider administering vitamin D supplementation to correct any vitamin D deficiency.
The increased possibility of COVID-19 transmission, potential vitamin D deficiency and the increased pressure on the healthcare systems due to other infectious diseases may lead to an increased mortality rate from COVID-19 in India during monsoon. Establishing the efficacy of vitamin D supplementation/sunlight exposure would be a significant advance in the control of COVID-19 pandemic in India during monsoon. This topic in India needs urgent attention from medical researchers around the world. Additionally, government and healthcare providers need to urgently plan to mitigate the impact of COVID-19 on public health by addressing these topics as early as possible.

1. Rolling updates on coronavirus disease (COVID-19). World Health Organization (2020).
2. Gupta, E., Dar, L., Kapoor, G. & Broor, S. The changing epidemiology of dengue in Delhi, India. Virol. J. 3, 1–5 (2006).
3. Laneri, K. et al. Forcing Versus Feedback: Epidemic Malaria and Monsoon Rains in Northwest India. PLoS Comput. Biol. 6, (2010).
4. Kalippurayil Moozhipurath, R., Kraft, L. & Skiera, B. Evidence of Protective Role of Ultraviolet-B (UVB) Radiation in Reducing COVID-19 Deaths. (2020) doi:10.2139/ssrn.3586555.
5. Grant, W. B. et al. Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Nutrients 12, 988 (2020).
6. Lanham-New, S. A. et al. Vitamin D and SARS-CoV-2 virus/COVID-19 disease. BMJ Nutr. Prev. Health (2020) doi:10.1136/bmjnph-2020-000089.
7. G, R. & Gupta, A. Vitamin D Deficiency in India: Prevalence, Causalities and Interventions. Nutrients 6, 729–775 (2014).
8. Holick, M. F. Vitamin D deficiency. N. Engl. J. Med. 357, 266–281 (2007).
9. India’s Coronavirus Death Toll Spikes. Time
10. Chadha, M. S. et al. Dynamics of Influenza Seasonality at Sub-Regional Levels in India and Implications for Vaccination Timing. PLoS ONE 10, (2015).
11. Dhara, V. R., Schramm, P. J. & Luber, G. Climate change & infectious diseases in India: Implications for health care providers. Indian J. Med. Res. 138, 847–852 (2013).

Corresponding Author:

Rahul Kalippurayil Moozhipurath

Faculty of Economics and Business, Goethe University Frankfurt, 60629 Frankfurt Germany.


Telephone: +4915213010589

Fax: +496979835001


Prashanth Kulkarni

Department of Cardiology, Care hospitals group, hi-tech city, Hyderabad, India, 50032.

Contributors Statement
RKM is the primary author and conceptualized the blog. PK edited the blog. Both RKM and PK approved the final version of the blog.
The authors did not receive any specific grant for this blog from any funding agency in the public, commercial or not-for-profit sectors.
Competing Interests
RKM is a PhD researcher at Goethe University, Frankfurt. He also is an employee of a multinational chemical company involved in vitamin D business and holds the shares of the company. All other authors declare no competing interests. The views expressed in the paper are those of the authors and do not represent that of any organization.
We would like to acknowledge Dr. Christy Susan Varghese for her assistance in the review.

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