A few countries are yet again reporting a surge in COVID-19 cases. In Singapore, reports suggest that the number of infections went from 22,094 to 32,035 in just a week, with an increase in the number of hospitalisations and ICU cases, according to Singapore's Health Ministry.
The United States of America has also witnessed an uptick of coronavirus cases in the country, with the highest prevalence so far this season in Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin, according to the US Centers for Disease Control and Prevention's (CDC) emergency rooms and wastewater sampling data. Data suggests that the rate of hospitalisation has also increased in the country, especially among senior citizens, middle-aged adults and children under age 4.
It is currently unclear as to what exactly is causing the spike in some parts of the world. Is it an outcome of waning immunity or the emergence of new variants, or could it be negligence? We at OnlyMyHealth spoke with experts to get some answers and to understand the role of booster shots.
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What Could Be Causing The Surge Of COVID-19 Cases?
Health authorities in the US and Singapore, where COVID cases are currently on the rise, attribute the spike to waning immunity, the emergence of new sub-variants, and unrestricted travel and gatherings during the holiday season.
However, speaking with the OnlyMyHealth team, Dr Harshad Limaye, Senior Consultant-General medicine, Nanavati Max Super Speciality Hospital, Mumbai, said, "If waning vaccine immunity were the sole reason, people in India should also be experiencing an increase in cases."
He added, "In India, only one booster was permitted for everyone, and subsequently, none of us have received a vaccine for the past two years. Yet, we aren't reporting a surge in COVID cases. Therefore, waning vaccine immunity alone might not be the cause, indicating there could be additional factors at play."
Dr Joydeep Ghosh, Consultant Internal Medicine, Fortis Hospital, Anandapur, Kolkata, said, “There is evidence suggesting that vaccine immunity against COVID-19 may wane over time, which can contribute to an increase in breakthrough infections (infections in vaccinated individuals), especially with the emergence of new variants.”
Currently, HV.1 remains the predominant COVID strain in the US, followed by EG.5 and FL.1.5.1. Some of the sub-variants of Omicron that are still circulating include EG.5, XBB.1.16.6, and XBB.1.16.11.
Role Of Booster Shots
Booster shots are additional doses of a vaccine given to individuals to enhance and reinforce the body's immune response to the virus, especially when the effectiveness of the initial vaccine may have decreased over time or if new variants tend to arise.
According to Dr Limaye, booster shots revitalise one's immune memory cells, prompting a surge in antibody production. These antibodies are the frontline defence against the COVID virus and serve as a reminder to your immune system.
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Is It Time To Get Another Booster Dose?
Dr Limaye said, “The recommended intervals for booster doses vary based on several factors. These include the unique immunobiology of each vaccine and considerations within different countries, such as their healthcare infrastructure and economic aspects.”
He added, “Each vaccine has its own specific guidelines regarding booster doses, and these recommendations might also differ from one country to another. Therefore, there's no fixed interval for booster doses; it's determined by multiple factors and guidelines specific to each vaccine and country.”
In the US, the CDC advises all people ages 6 months and older to get one dose of an updated COVID-19 vaccine (Pfizer-BioNTech, Moderna, or Novavax) to protect against serious illness from COVID-19.
For people who are moderately or severely immunocompromised, the health body recommends getting additional doses of updated vaccines.
However, in India, there are no definitive guidelines for booster doses, said Dr Limaye, adding that previously, only one booster shot or precautionary dose was available for everyone through the CoWIN app. Individuals who have already received the three doses are currently unable to register for additional booster shots via the app, he shared further.
Who Is Eligible For Precaution Dose In India?
The COVID-19 precaution dose was first made available on April 10, 2022.
"All those who are more than 18 years of age and have completed 9 months after the administration of the second dose would be eligible for the precautionary dose," an official statement from the Union Health Ministry stated.
The gap between the second dose and the booster dose is supposed to be 9 months, or 39 weeks. In addition, the guidelines advise against the mix and match of COVID vaccines, meaning that if you previously received Covaxin, you can only receive the Covaxin booster dose, and the same goes for Covishield.
