**1. Introduction**

The coronavirus disease 2019 (COVID-19) proclaiming millions of lives, is an infectious respiratory disease affecting the lungs. COVID-19 is devastating mainly in patients of old age and with co-morbidities like obesity, cardiovascular complications etc. COVID-19 is caused by recently recognized coronavirus termed as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [1]. COVID-19 outbreak was instigated in December 2019 from the Wuhan city of China, which is rapidly spreading worldwide and badly impacted the entire world [2]. The COVID-19 pandemic is currently the prevalent world health crisis and a daily large number of new cases is reported around the world [3, 4]. By June 24, 2021, the mortality rates raised to 3.9 million among 180 million confirmed cases of COVID-19. Currently, the world healthcare system is in severe crisis due to the constant and varied challenges created by COVID-19. Initially, due to the lack of understanding regarding novel coronavirus and vaccines or any treatment for the COVID-19, governments officials globally implemented various non-pharmaceutical interventions (NPIs), such as the utilization of masks, social distancing, hand-washing, remote working, closures of schools and colleges, restrictions on public gatherings, fourteen days quarantines, for the slow transmission of the disease [5]. These measures are found to be effective in mitigating the number of cases [6, 7], however, they lead to a considerable impact on the social, economic [8] and psychological wellbeing of the society [9].

Government's professionals, pharmaceutical companies and professionals in the health care system are taking great efforts to manage and combat the disease across the world. To alleviate the burden on society, a massive effort is being made by health care professionals worldwide to develop and get access to different vaccines [10, 11]. Vaccination has been started around the globe after a year of the first reported cases of COVID-19 [12]. Vaccines were developed and have been found successful in decreasing the number of patients affected with COVID-19 as well as the severity of the disease, however, it is not completely avoiding the risk of being affected with COVID-19. Additionally, new strains of coronavirus are also gradually identified. Recently it is found that novel coronavirus is having various mutations. This means that there are slight changes in the genetic composition of the virus. The Delta-plus variant is a mutated version of the Delta variant (the virus that wreaked havoc in the second wave). Delta plus is considered highly infectious. The virus can potentially dodge immune response, vaccines and antibody therapies. However, more research has to be done in this context. Few cases have been recorded in some states of India. The Government official has classified it as a Variant of Concern (VOC). There is no certainty regarding delta plus and the current numbers cannot determine any particular trend. Certain vaccines work against the Delta Plus variant, but they show 3 to 8 times less efficacy as compared to other variants. There are no conclusive reports about these variants but we should not keep our guards down [13, 14]. The United States Food and Drug Administration (U.S. FDA) approved the antiviral drug, remdesivir (Veklury), for treating COVID-19 affected patients requiring hospitalization. Remdesivir approved to be administered in the health care setting or hospital that is efficient enough of affording acute care comparable to inpatient hospital care. This approval of using remdesivir for treating COVID-19 does not include the entire population rather it is only approved for hospitalized patients who are adults and pediatric (≥12 years of age) with a bodyweight of at least 40 kilograms [15]. Moreover, health care systems are facing huge difficulties in combating the enormous demands of medicines and vaccines. Thus, providing additional therapies for preventing and curing the disease is an important step in combating this pandemic. Currently, the worldwide impetus is unabated, and a third wave is also predicted.

India and China are known for their rich history of traditional medicine [16]. Indian households are being considered as a hub of natural products, consisting of a plethora of pharmacologically active ingredients inspired by the traditional medication system (Ayurveda) [16]. Complementary and alternative medicines (CAMs) have emerged as a ray of hope in these times [17]. The following book chapter focuses on 'the role of CAMs in the prevention, treatment and management of COVID-19'.
