Virus surges will continue periodically, says IIPH Director

Only way to reduce risk is permanent change in people’s behaviour and adequate vaccination

COVID-19 infections will arise and abate at periodic intervals due to ‘transient herd immunity’ (pool of protected individuals in the population) that each wave of the infection brings, in the absence of an effective vaccine covering a significant proportion of the population. The only way to reduce the risk is adherence to strong governmental monitoring, surveillance and a permanent change in people’s risk behaviour, explain public health experts. The infection was previously high in August-September 2020 and October-November 2020, when a significant proportion of the population was infected. While some studies had reported about more than a third of the population having antibodies, the actual number of infected may have been much higher taking into consideration the asymptomatic and mild cases, explains Public Health Foundation of India (PHFI)-Indian Institute of Public Health (IIPH), Hyderabad, Director Dr. G.V.S. Murthy This may have led to the tipping point or ‘transient herd immunity’ with the virus not finding enough susceptible people to infect. As viruses search for hosts to infect for their survival, they mutate to adapt to the environment. Studies have also shown that the infection induced immunity may not last more than 6-9 months. In fact, a study in Denmark showed that the drop-off of antibodies in the older population is up to 60% in six months. It means more of the population becomes susceptible due to reduced antibodies leading to a surge, in the absence of vaccination, he says.