Widely distributed vaccine will produce herd immunity

The argument

A coronavirus vaccine would drastically reduce the herd immunity threshold—the percentage of the population that needs to be infected or contact the disease to gain herd immunity. In data collected from a U.S. Food and Drug Administration survey, the consulting firm McKinsey and Company found that a vaccine with moderate effectiveness would still reduce the herd immunity threshold to 30 or even 20 percent. For context, without a vaccine, the U.S. is currently at a 2.2% infection rate, the UK has a less than 1% infection rate, and Brazil has an infection rate of about 2.5%. Scientists have estimated that the coronavirus herd immunity threshold could be as low as 43% without a vaccine, but that would involve nearly half of the population having been infected with the virus. A vaccine will drastically lower that percentage. Health officials in the U.S. and India have estimated that a vaccine for the virus will be available by early 2021, with the Union Health Minister Harsh Vardhan saying that one in five people will be vaccinated by July. Dr. Anthony Fauci, one of Americas most famed disease analysts, said that while a vaccine could be available by January, it will not be administered to large portions of the population until the middle of next year. If coronavirus case counts continue to steadily dimish, a new vaccine will stop the pandemic by July of 2021.

Premises

Counter-arguments

The likelihood people will actually take a vaccine is still up in the air. While a vaccine could help curb the virus by decreasing the herd immunity threshold, a recent poll shows 49 percent of Americans said they would definitely not take a COVID-19 vaccine.

Rejecting the premises

[Rejecting P1] The threshold calculation assumes a vaccine that blocks transmission rather than only disease. Where a vaccine reduces severity more than it reduces spread, the threshold does not fall as modelled — and estimates produced before any candidate had reported results were necessarily speculative. [Rejecting P2] Availability and administration are different things, and the premise treats a projected approval date as a delivery schedule. Manufacturing, distribution, cold-chain requirements and uptake each impose their own delays, and uptake was in serious doubt at the time the argument was written. [Rejecting P3] 'The pandemic will effectively end' assumes a static virus. Variants that alter transmissibility or partially evade immunity reset the calculation, and immunity that wanes means the threshold has to be met repeatedly rather than once. [Rejecting C] The conclusion is global in form and national in evidence. Ending a pandemic requires vaccination across countries with very unequal access, and the premises consider only a handful of wealthy ones.