Should Delhi residents take a booster Covid shot as cases rise? Here's what a doctor says

Indian Express

27-05-2025

Delhi has reported a total of 104 active Covid-19 cases so far, the third highest after Kerala and Maharashtra. As per the Centre's Covid dashboard, the surge in the national capital happened over the last week when 99 cases were added from May 19.
Should residents be worried about the surge in India, which follows a spike in cases in South Asia? Are booster shots needed?
Dr Rakesh Gupta, Senior Consultant, Internal Medicine, Indraprastha Apollo Hospital, sheds light on some frequently asked questions:
Why are cases rising in Delhi?
Covid-19 cases are rising everywhere due to a combination of waning immunity, relaxed public behaviour, and the emergence of new variants with higher transmissibility.
Many people have resumed pre-pandemic routines such as large gatherings, travel, and not wearing masks, especially in urban areas. Additionally, immunity from earlier infections and vaccines administered over a year ago is decreasing, making people more susceptible. Changes in weather and air quality can also influence respiratory infections, contributing to the surge. Limited testing may be underestimating actual cases, allowing community spread to go unnoticed until hospitalisation numbers begin to rise.
Will the vaccines taken almost two years ago still provide protection?
Vaccines taken two years ago may still offer some protection, particularly against severe illness and hospitalisation, but their effectiveness against infection has likely diminished significantly.
This is because over time, immunity from vaccines wanes, especially in the face of new variants that are more adept at immune escape.
However, those who received booster doses — especially updated ones — may still have more robust protection. The primary series, although outdated against some newer strains, still helps the immune system recognise the virus faster than in unvaccinated individuals. It's advisable that senior citizens and those with comorbidities should consider getting a booster doses, if eligible.
Why did the surge happen in South Asia?
The recent Covid-19 surge in South Asia stems from a mix of socio-economic, climatic, and healthcare-related factors. Many countries in the region have densely populated cities, making social distancing difficult.
Public fatigue toward COVID-appropriate behaviour has led to a sharp decline in mask usage and hygiene practices. Cross-border travel, underreporting, and uneven vaccine booster coverage contribute to the resurgence. Seasonal changes — particularly the shift from warm to cooler weather — also play a role in viral spread. Moreover, health systems in some areas are not fully equipped to detect and respond rapidly to new outbreaks, enabling the virus to spread unchecked.
What does the current surge signify?
It signals that Covid-19 remains a public health threat, even if it's no longer dominating headlines. It suggests that the virus continues to evolve, potentially outpacing existing immunity from prior infections or vaccinations.
The rise in cases may lead to localised strain on healthcare systems, especially if accompanied by an increase in hospitalisations or severe cases. It is also a reminder to maintain vigilance — especially for vulnerable groups such as the elderly or immunocompromised. While full lockdowns are unlikely, this surge may prompt governments to reintroduce preventive measures and reassess their vaccination and public health strategies moving forward.
What are the characteristics of this strain?
The new strain appears to have mutations that make it more transmissible than earlier variants, though early reports suggest it may not cause significantly more severe disease. Like previous Omicron subvariants, it might evade immune protection to some extent, leading to reinfections even in those previously vaccinated or infected. Common symptoms remain largely respiratory — cough, fever, fatigue — but anecdotal reports mention faster spread within households. Researchers are closely monitoring whether it impacts hospitalisation rates. However, severity seems manageable for most healthy individuals. The real concern lies in its potential to disproportionately affect older adults or people with pre-existing conditions.
When do we need to worry?
If the number of severe cases and hospitalisations rises significantly, especially among vaccinated or previously healthy individuals. Additionally, if a new variant begins to evade immunity to the extent that it causes widespread reinfections or longer illness duration, it would indicate the need for renewed public health measures. We should also be alert if essential services, like healthcare staffing, start to get disrupted due to illness.
Another red flag would be rising mortality, particularly among vulnerable populations. Until then, while widespread panic is unnecessary, maintaining cautious behaviour and staying informed through credible sources is prudent.
Do we need to start testing more?
Yes, increased testing — particularly among symptomatic individuals, healthcare workers, and the vulnerable population — is important during a surge. Testing helps identify outbreaks early and allows for timely isolation, reducing the virus's spread. It's also essential for tracking which variants are circulating and determining the appropriate public health response. While mass testing of asymptomatic individuals may not be necessary, targeted testing in high-risk zones, workplaces, and schools can help prevent larger outbreaks. If testing rates remain low, it becomes difficult to assess the true scale of the surge or to implement effective containment strategies in affected communities.