The immune system is the protecting shield for the human against any infection caused by germs or pathogens. It produces antibodies against the infectious antigens and takes time. Each antibody can recognize one specific antigen. On exposure to an antigen for the first time, the immune system takes time to recognize and develop the specific antibodies.

The vaccine is a product that stimulates a human immune system to produce antibodies against the disease without being affected by the disease first, thus provides immunity against a specific disease. Vaccines contain the same germs that cause disease, which is either killed or attenuated and weakened to an extent that they don’t cause sickness but stimulates the immune system to respond similarly as during the actual pathogen in the first reaction. Some vaccines contain only a part of the disease germ. A vaccine stimulates the immune system ^1,2.

Sometimes vaccines need to be administered in multiple doses, given weeks or months apart to allow for the formation of long-lived antibodies and the development of memory cells. This trains the body to fight the specific disease-causing organism, builds up the memory cells in the human body against the pathogen and enhances the protection if exposed to a similar pathogen in future.³

The constantly changing or mutating nature of the Flu viruses make it essential to get vaccinated every season. Hence new, vaccines are made each year to protect against flu viruses. Flu spreads mainly by droplets when infected people speak, cough, or sneeze, and these droplets may enter the mouths or noses of people who are in the nearby surrounding and may be inhaled.  It takes almost 2 weeks to develop protection against the flu after being vaccinated. ⁴

Studies in the US have shown that people previously infected with COVID, had antibodies, produced by the memory B cells of the immune system and served as an immune reservoir that contains a diverse collection of antibodies. These people also developed a long-lasting defense against the SARS-CoV-2, virus. Also, it was observed that people who had been vaccinated even with one dose of vaccine had an enhanced number of antibodies and were resistant to the most concerning SARS-CoV-2 variants, found in UK, South Africa and New York ². 

Several child specialists suggest that children should be vaccinated as it could decrease the risk of flu illness and hospitalization in children and serve to be life-saving. Also, the severity and complications of flu infection may be reduced and can control the spread among family and friends ⁴.

Throughout India, different pediatrics are of the view that vaccinating children with seasonal flu shots would reduce the need for COVID-testing, and protect children from seasonal flu and help to distinguish if the cough, cold and fever in children are due to Covid-19 or influenza. Additionally vaccinating children under 10 with flu shots may also be in preventing co-infections if affected with COVID-19 and reduce the spread, the severity and thus decrease the burden on the healthcare system and rush to hospitals ⁵.

Reference:

1. https://www.cdc.gov/vaccines/vpd/vpd-vac-basics.html
2. (https://health.economictimes.indiatimes.com/news/industry/vaccines-boost-natural-immunity-against-covid-19-study/83140652)
3. https://www.who.int/news-room/feature-stories/detail/how-do-vaccines-work
4. https://www.cdc.gov/vaccines/parents/diseases/flu.html
5. (https://www.newindianexpress.com/nation/2021/jun/02/flu-shots-for-children-can-cut-covid-rush-at-hospitals-experts-2310578.html)