As COVID-19 cases rise, should you consider a booster vaccine?

Although the majority of infections are relatively mild due to widespread immunity and the lesser severity of new variants, experts have warned against complacency.

India is seeing a gradual rise in COVID-19 cases, with active infections crossing the 1,000 mark nationwide.

Kerala currently leads with over 430 active cases, while cities like Chennai and Kolkata are also reporting localised surges.

Experts believe the increase is driven by the Omicron subvariant JN.1 and its offshoots.

With infections climbing again in parts of the country, more people – particularly those over 60 or with underlying health conditions – are asking a familiar question: Do I need another vaccine dose?

Doctors, virologists and public health experts say the answer, from a clinical perspective, is yes.

While there’s currently no national guidance on new booster doses – leaving many unsure of what to do – doctors say those who are immunocompromised or receiving cancer treatment should consider getting an additional shot.

“As of now, annual COVID-19 vaccination is recommended for those at risk of developing severe illness, especially those above 65 years,” said Dr Narayana Subramaniam, Senior Consultant and Director of Head and Neck Surgery and Oncology, and Director of Clinical Innovation at Sparsh Hospitals, speaking to South First.

Inoculation strategy

The United States currently has an aggressive, universal Covid19 vaccination strategy, where annual booster shots is recommend for nearly everyone over six months of age.

In contrast, many European countries offer boosters only to older adults or those with high-risk health conditions.

Notably, a recent paper published in The New England Journal of Medicine by Indian-origin researcher Dr Vinay Prasad, along with Dr Martin Makary and colleagues from the US Food and Drug Administration’s Centre for Biologics Evaluation and Research, calls for a more evidence-based, risk-stratified approach to vaccination.

The FDA has said it will support rigorous clinical trials – especially in low-risk groups – to ensure booster strategies are backed by scientific evidence.

These trials will focus on key outcomes such as symptomatic infection, hospitalisation and death, aiming to assess whether annual boosters are truly beneficial for people with prior infections or multiple vaccine doses.

For now, doctors in India stress that the decision to get a booster should be made in consultation with a healthcare provider.

They recommend additional doses mainly for those with comorbidities who are immunocompromised and at higher risk.

Why most COVID infections are mild – and who still needs to be careful

Dr Rajeev Jayadevan, Co-Chairman of the National IMA COVID Task Force in Kerala, says that while COVID-19 cases are once again rising in parts of Asia, including India, the infections are generally milder than in previous waves.

He attributes this to two key factors: the currently circulating variants, which tend to be less severe, and widespread immunity built up through earlier vaccinations and past infections.

This population-level immunity continues to protect most people from serious illness or death.

However, Dr Jayadevan points out that immunity against infection is short-lived and tends to return to baseline levels within about six months.

“An additional vaccine dose is unlikely to offer long-term protection for most people. By the time a new variant appears, the protection from that dose may no longer be effective,” he said.

Noted virologist and public health expert Prof Jacob John agreed that while these new sub-variants are less threatening than earlier strains like Alpha, Beta or Delta, they still require close monitoring.

“The early variants caused lung damage by cutting off blood supply, leading to what appeared to be pneumonia but was actually a vascular issue,” he said.

“That changed with the arrival of Omicron in December 2021.”

Omicron and its sub-variants have mostly affected the upper respiratory tract and typically spare the lungs. This shift means most infections now do not result in pneumonia, low oxygen levels, or organ failure.

“Except for those with serious underlying conditions, these newer sub-variants usually cause only mild illness,” Prof John said.

Still, he warned that for the elderly and those with chronic illnesses such as heart or lung disease, even a mild infection can become dangerous.

How the virus is evolving – and what it means for immunity

Prof John also drew attention to a blind spot in public health: influenza.

“Influenza remains a deadly disease among the elderly, yet it rarely gets the same level of public or media attention,” he said.

When it comes to COVID-19 vaccination, he outlines three broad groups:

• Those who were fully vaccinated and may have gained further immunity from mild or unnoticed infections
• Those never vaccinated but exposed through repeated infections
• And young children born after 2022, who remain largely unexposed to the virus

Despite widespread immunity, the virus continues to evolve.

“Every major variant that became dominant did so by evading existing immunity. That’s how Omicron displaced earlier variants,” Prof John said.

Sub-variants of Omicron, he added, may be only slightly better at evading immunity – but even that small advantage is enough to make them dominant for a time.

Currently, the World Health Organisation classifies these emerging sub-variants as “Variants of Interest,” not “Variants of Concern.”

Still, Prof John cautions against complacency: “No one can predict what the virus will do next. That’s why we must stay alert.”

For high-risk individuals – such as cancer patients, transplant recipients, and older adults – experts recommend an additional vaccine dose.

In India, two booster options are currently available:

• Bharat Biotech’s intranasal vaccine (iNCOVACC)
• Gennova Biopharmaceuticals’ Omicron-specific mRNA booster.

Doctors, particularly those treating immunocompromised patients, are best placed to advise on these options.

Meanwhile, Dr Jayadevan also cautioned that COVID-19 is an airborne disease.

“The virus spreads like cigarette smoke in closed, poorly ventilated spaces,” he said.

“Staying home if you have a fever or respiratory symptoms, avoiding non-essential visits to hospitals, and wearing masks in high-risk settings can help limit the impact of this wave.”

Who should consider a booster dose?

Based on guidance from Prof Jacob John, certain groups are more vulnerable to severe illness from COVID-19 and should consider an additional vaccine dose – after discussing it with their healthcare provider.

Those at higher risk include:

• Older adults, especially those over 60
• Immunocompromised individuals, such as those:
  • Undergoing cancer treatment
  • Living with HIV/AIDS
  • On immunosuppressive therapy (e.g. for autoimmune conditions)
  • Who have received organ transplants
• People with serious underlying health conditions, including:
  • Chronic heart disease
  • Chronic lung diseases like COPD or asthma
  • Severe hypertension
  • Diabetes
  • Kidney disease
  • Multiple comorbidities that increase overall risk
• Healthcare professionals treating high-risk patients, such as:
  • Oncologists
  • Transplant specialists
  • Primary care doctors managing vulnerable patients

These individuals face a greater risk of complications, even from mild COVID-19 infections, and may benefit from a booster using the vaccines currently available in India.