Should You Get a Fourth Dose of COVID-19 Vaccine?

Pros and Cons: Should You Get a Fourth Dose of COVID-19 Vaccine?

Hong Kong was hit hard during the fifth wave of the COVID-19 outbreak early this year, resulting in more than 70,000 people infected daily with the Omicron variant at its peak

As a result, the Hong Kong government implemented stricter COVID-19 guidelines following Beijing’s “dynamic-COVID” policy. This includes the enforcement of flight bans, a mandatory quarantine period of 7 days (formerly 14 or 21 days), restrictions on public services, and the threat of family separation in case one member tests positive for the virus (including infants and children).

To help flatten the curve, the Hong Kong government intensified its inoculation drive among residents, especially the elderly who have a weaker immune system. The Health Authority, alongside government officials, launched a city-wide vaccine pass, mandating residents be vaccinated with three doses to enter public premises, including restaurants, bars, sports facilities, and entertainment venues.

In March, medical experts in Hong Kong called on residents aged 60 and above to have their fourth vaccine dose or a second booster shot apart from the three-dose primary vaccination series. However, uncertainties over a fourth dose linger among residents, particularly senior citizens. Their hesitation stems from a variety of reasons such as lack of confidence in the government, no clear guidance from the doctor, and limited knowledge in using vaccine-related technology, among others.

The question is: Is vaccinating people every four to six months sustainable and affordable? Here’s what you need to know about the fourth dose.

What is a Fourth Dose? 

The U.S. Food and Drug Administration (FDA) approved the emergency use of the fourth dose for the elderly and immunocompromised individuals on March 29.

Pfizer-BioNTech and Moderna vaccines are the only brands that have been approved for use in COVID-19's fourth dose.

The second booster dose shall be administered at least four months after receiving the first booster dose. Individuals over 50 years old and young patients aged 12 years old and under with immunocompromised conditions may get the fourth dose.

What Does Research Say About the Fourth Dose?

FDA’s Center for Biologics Evaluation and Research director Peter Marks cited in a news release on March 29 a recent study showing “some waning of protection over time against serious outcomes from COVID-19 in older and immunocompromised individuals.”

“Based on an analysis of emerging data, a second booster dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccine could help increase protection levels for these higher-risk individuals,” he said. Separately, an observational study published in the New England Journal of Medicine of showed that the relative vaccine effectiveness in days 14 to 30 after a fourth dose ranged between 52% and 76%.

What are the Potential Benefits of Having a Fourth Dose?

Just like the primary COVID-19 shots, the main objective of getting a fourth dose is to modestly increase protection against the virus by restoring antibody levels.

Israeli Prime Minister Naftali Bennett said antibodies had increased by five-fold after a week of having the fourth dose, citing the preliminary results of the Israeli study.

What are the Drawbacks of Getting a Fourth Dose?

Medically speaking, vaccines are regarded as safe and administering another dose does not necessarily impose a threat on human health. Nevertheless, there are still some disadvantages that an individual may encounter in such circumstances.

COVID-19 vaccines have side effects like headache, fever, fatigue, and joint aches. These side effects, however, cannot be ignored for older people. University of Washington immunologist, Dr. Marion Pepper told The New York Times that recurring or repeated vaccination may result in the decline of antibody responses and weaken vaccine effectiveness.

The fourth time a person is exposed to the virus (whether by illness or vaccination) does not guarantee that their immunity will become stronger. Thus, it potentially makes a person’s body less responsive to future variants.

Furthermore, scientific research suggests that vaccines administered at greater time intervals may result in a stronger and longer-lasting immune response.

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