Covid vaccine ‘won’t prevent infection but is a weapon to fight it’

By Thai Newsroom Reporters

QUESTIONS have arisen about the effectiveness of the Pfizer vaccine in protecting people against the “double mutant” coronavirus variant that emerged in India.

This issue came to the limelight after Dr Rajendra Kapila, an infectious disease expert at Rutgers University in US, died upon getting infected with the Indian strain during a visit to see his parents despite having had two Pfizer vaccine shots.

One obituary said, “Looks like the vaccine may not be effective with new variants.”

However, the key point which the majority of the people tend to miss is that a vaccine does not protect people from getting infected but does minimize the impact of the virus.

In an interview with India TV, AIIMS Director Dr. Randeep Guleria underscored that getting vaccinated does not mean that a person will not get infected. Vaccination is a weapon to fight the novel coronavirus but it does not prevent it. 

He added that the virus can multiply in the nose and throat so it is very important to continue the Covid appropriate behaviour like wearing a face mask, social distancing and following other safety precautions.

On India’s huge spike in the number of coronavirus cases with this soaring over 300,000 for almost a fortnight now, Dr Guleria said, “There are various reasons behind the sudden spurt in cases. In January-February, when cases started to decrease people lowered their guards as they thought coronavirus is now on its way out. People neglected Covid appropriate behaviour which is the main reason behind the sharp rise in cases.”

Meanwhile immunologist Dr Larisa Labzin and vaccine expert Dr Kylie Quinn told ABC News that assessing whether a vaccine prevents infection (rather than the development of disease) is particularly challenging to study in humans, partly for ethical reasons.

In coronavirus vaccine trials, the drug companies waited for people to get sick to determine whether the vaccine offered any protection.

But to work out if the vaccine prevents infection, Dr Labzin said researchers would ideally vaccinate people and then deliberately expose them to the virus — to see if they get infected, even if they don’t develop symptoms.

These trials, known as human challenge trials, are usually only performed when a specific treatment (for whatever disease you’re trying to prevent) is available, which we don’t yet have for Covid-19, Dr Quinn said.

“That’s why in these first interim results we’re just talking about: do people get sick or not?” she said.


Top and Home Page: Doctors getting ready to give a Covid jab. Photos: Getty Images published by BBC


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