Soaring Infections Undermine Herd Immunity Claims

  • By Bae Jun-yong

    November 25, 2021 09:26

    Soaring coronavirus infections cast increasing doubt on the theory that herd immunity would be achieved once 70 or 80 percent of Koreans are vaccinated. The vaccination rate for all age groups has reached 79.1 percent and 91.1 percent for adults, but infections surged over 4,000 on Wednesday.

    The government began vaccinations in March, hoping to achieve herd immunity by November. But the emergence of the more virulent Delta variant, which is three times more contagious, thwarted such hopes.

    Now health authorities claim that around 83 percent of the population must be vaccinated to achieve herd immunity against the Delta variant, but even 100 percent will not lead to zero COVID since the vaccines are only 60 to 80 percent effective in preventing infections.

    People wait in line to get tested for coronavirus at a makeshift facility in Seoul on Wednesday. /Yonhap

    Jeong Eun-kyeong, the chief of the Korea Disease Control and Prevention Agency, warned earlier, "It appears difficult to achieve herd immunity, because the Delta variant is highly contagious and weakens the preventive effects of vaccination."

    This is why countries around the world have effectively abandoned the goal of herd immunity and are switching to minimizing damage and vaccinating high-risk groups to reduce fatalities. Instead they hope for the virus to become endemic, so that smaller outbreaks can be controlled.

    Portugal has vaccinated 86 percent of its population and Ireland 89 percent. They were touted as role models in Europe when daily infections fell to 200 to 300. But recently they have surged to 2,000 to 3,000, prompting their governments to consider re-imposing lockdown.

    Health experts are flailing. Earlier, vaccine immunity was assumed to last for at least six months, but it seems to wear off after about four to five months now, so the new orthodoxy is booster shots even before the entire population is vaccinated.

    Some vaccines are losing credibility entirely. Korea has effectively abandoned AstraZeneca's vaccine because it seems to wear off about three months after injection. This is a problem for older Koreans and other vulnerable people who were given the jabs more than three months ago and now urgently need booster shots, which have only begun recently.

    In August, when the Delta variant began spreading like wildfire here, some health experts urged the government to administer booster shots to vulnerable groups instead of seeking to boost the number of first vaccinations, but the government insisted on inoculating 70 percent of the population by the end of October.

    Ma Sang-hyuk of the Korea Vaccine Society said, "The government's touting of herd immunity without considering ample research ended up fomenting distrust."

    The daily tally of new infections stood at 3,938 with 612 severe cases as of Thursday morning.

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