“Antibodies are the most powerful weapon in combating COVID-19,” says Dr. Arun Sharma of ICMR-Jodhpurs.

Antibodies are the most powerful weapon in defeating the coronavirus, and vaccines provide long-term immunity by producing the right antibodies in the body. Natural infections also lead to the formation of antibodies, providing some protection against reinfection. Dr. Arun Sharma, MD, a community medicine expert and director of the National Institute for Non-Communicable Diseases-ICMR, Jodopur, said that the relationship between infection and antibodies, when and whether to check for the presence of antibodies, and when they are. Learn how to help fight viruses.

What is the relationship between infectious diseases and antibodies?

When a new virus affects a population, the body’s immune system recognizes it as a foreign body and develops antibodies against it. Since it takes time to develop antibodies, infection can cause serious illness depending on the pathogenicity of the virus, viral load, and human immunity. However, the next time the same pathogen attacks, the antibodies that are already in the body are rapidly activated, reducing the severity of the disease.

For example, rotavirus affects the digestive system. In the 1990s, it caused severe diarrhea in children, but it was observed that children gradually developed antibodies against it, reducing the severity of the disease. But then it began to affect foreign travelers to India, as they were not exposed to the virus in their country. So this is how the new virus works unless it mutates to become more contagious or pathogenic.

What is the ideal post-vaccination time interval to check the level of antibodies to COVID-19 in a person? Which test should I choose?

A well-equipped pathology laboratory can test for the presence of antibodies in the blood. There are two types of antibodies that are produced in the body in response to an infection. The first reaction is mediated by IgM, which lasts for a short time, after which the body produces IgG antibodies. Therefore, immediately after COVID-19 infection, IgM levels are high, but these antibodies decline after 6 weeks. IgG antibody could be detected after 2-3 months. After vaccination, if you want to know if the vaccine has led to antibody production, you should use IgG.

There are two types of immunity, humoral and cell-mediated. Antibodies in the blood fight infection in diseases such as polio, hepatitis, and Covid-19, but cell-mediated immunity plays a greater role in diseases such as tuberculosis. Basically, there are two main types of immune cells. B cells (humoral antibodies) that form antibodies in the blood and T cells that are involved in cell-mediated immunity. T cells kill and eat up pathogens, but antibodies in the blood bind to pathogens, neutralize them, and prevent them from invading human cells. For example, in COVID-19, the antibody binds to the peaplomer present in the virus, helping the virus invade and replicate. Antibodies ensure that the disease does not get worse.

Some experts say that vaccines lead to long-term cell-mediated immunity. Can you explain what that means to the average reader?

There are two types of T cells: T helper cells and T suppressor cells. Helper cells recognize and memorize antigens and help B cells rapidly replicate antibodies in the event of reinfection. The COVID-19 vaccine helps T helper cells memorize antigens. And when a person catches an infection, these helper cells help B cells make antibodies to it. They remain active for a longer period of time.

Should I have an antibody test after vaccination? Why do some people not develop antibodies after vaccination?

Whether to test antibody levels after vaccination or after spontaneous infection is an individual choice. Thorough medical investigation is recommended for those who do not develop antibodies after vaccination. I think it could be a person’s genetic makeup or immune system-related issues that could lead to such a situation.

Why do some people still develop this disease, the so-called breakthrough infection, even after two vaccinations?

The COVID-19 vaccine stimulates the body to develop antibodies against the virus. However, these antibodies remain in the blood. SAR-Cov-2 enters the body through the mouth and nose. It replicates there and enters the lungs through the trachea. Therefore, antibodies can neutralize the virus as it moves from the lungs to the blood. Therefore, as soon as the virus enters the blood, the antibody attacks the virus and prevents it from entering other organs such as the brain, heart, and kidneys. Viruses can cause infections, but vaccines prevent it from causing serious illness or hospitalization. Therefore, the emphasis is on following COVID-appropriate behavior, even after vaccination.

Nasal vaccines can help kill the virus in the nasal passages. This happens with oral polio vaccines. The weakened viral vaccine forms a protective coating around the intestines when given orally. This coating does not allow the virus to cause an infection.

How accurate is the serum survey?

Serum research is a research method that helps policy makers come up with strategies to combat a pandemic. Random sampling is used to determine the prevalence of antibodies in the population. These antibodies tell you the extent of the infection. However, it is limited because the sample size is small and cannot represent the entire population of a large country like India. So you can’t and shouldn’t be alert.