Context: The number of COVID-19 cases in India has been steadily increasing with Maharashtra, Karnataka, Tamil Nadu, and Kerala accounting for the majority of new infections. A new virus subvariant- NB.1.8.1 was found in a sample and sent to India's genome sequencing consortium.
Relevance of the Topic:Prelims: Key facts about SARS-CoV-2 Virus.
SARS-CoV-2 Virus
Coronavirus (COVID-19) is a highly contagious viral illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
- SARS-CoV-2 is a novel beta coronavirus belonging to the same subgenus as the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East Respiratory Syndrome Coronavirus (MERS-CoV).
- Coronaviruses are positive-stranded RNA viruses with a crown-like appearance due to the presence of spike glycoproteins on the envelope.
- Like other RNA viruses, SARS-CoV-2 is prone to genetic evolution/mutation over time. This results in mutant variants that may have different characteristics than its ancestral strains.
- Origin: widely postulated to have originated from an animal, implicating zoonotic transmission.
- Transmission: Exposure to respiratory droplets carrying the infectious virus from close contact or droplet transmission from presymptomatic, asymptomatic, or symptomatic individuals.
- Vaccines: mRNA vaccines (Pfizer); viral vector vaccines (Covishield; Sputnik V); inactivated viral vaccines (Covaxin); DNA vaccines (ZyCov-D); protein subunit vaccines (Novavax).
SARS-CoV-2 has not disappeared. It has become part of a recurring cycle of illnesses, similar to the flu. Periodic waves of Covid-19, like other endemic respiratory diseases, are expected throughout the year.
Several factors could be contributing to the rise in cases:
- Waning immunity: Protection from vaccination or past infection decreases with time, leaving individuals more vulnerable to reinfection.
- New variants: Like other viruses, SARS-CoV-2 continues to mutate. Some of these new variants may spread more easily or evade immunity to a greater extent.
- Seasonal patterns: Respiratory viruses often spread more efficiently in colder or more humid periods.
- Not enough testing: Covid-19 is now considered endemic, and testing and genome sequencing efforts have been scaled back, delaying the identification of outbreaks.
- High-risk groups: Individuals with weakened immune systems or severe comorbidites remain especially vulnerable.