Plant-Based Vaccines Against Infectious Human Viral Diseases: Spotlight on HIV Vaccines

Infectious human diseases are caused by a host of medically important viruses such as the HBV, HCV, HIV, HPV, influenza, SARS-CoV-2, dengue, WNV, chikungunya and zika viruses. They result in severe morbidity and mortality in affected individuals and result in millions of deaths every year. Amongst all of them, the recently emerging SARS-CoV-2 is responsible for over 228 million cases worldwide with nearly 5 million cases of death reported (WHO 2021). Each of these viruses cause typical symptomatic disease: for instance, HBV and HCV affect the liver causing liver cirrhosis and hepatocellular carcinoma while the influenza virus and the SARS-CoV-2 mainly affect the respiratory tract. For the influenza virus, there occurs a high degree of variability of the viral hemagglutinin (HA) antigen which results in the high antigenic variability of the virus. The HPV mostly spreads through sexual activity and in severe cases, results in cervical cancer. The HIV also spreads predominantly through sexual activity and causes impairment of the body’s immune system leaving it susceptible to a host of bacterial and viral diseases. The Zika virus causes Guillain-Barre syndrome in adults [1-3] and microcephaly in fetus. For many of these viruses such as HIV, HCV and Zika viruses, there is no vaccine available even as these viruses mutate and evolve mechanisms to evade the body’s immune mechanisms. Importantly, there is a dearth of low-cost, easily administrable prophylactic and therapeutic vaccines for these diseases in developing countries where incidence of high rates of infectious viral diseases is reported and herein there lies a compelling need to generate plant-based vaccines against these deadly diseases [4,5].