COVID jabs much more effective than virus at preventing infection

A US study has found that the immunity afforded by COVID-19 vaccines is much stronger than that stimulated by infection with SARS-CoV-2 in unvaccinated individuals.

The report by the Centre for Disease Control and Prevention (CDC), based on an analysis of dozens of research studies and its own data, suggests that both vaccination and infection with the coronavirus provide robust immunity for at least six months.

Vaccines however are associated with "higher, more robust, and more consistent" immunity than infection, with unvaccinated people who had a recent infection five times more likely to be reinfected with SARS-CoV-2 compared to those who were fully vaccinated with the Pfizer/BioNTech or Moderna vaccines most widely used in the US.

"We now have additional evidence that reaffirms the importance of COVID-19 vaccines, even if you have had prior infection," said CDC director Rochelle Walensky in a statement.

The study strikes at the heart of an ongoing debate about vaccination strategy in the US, as the Biden administration tries to boost take-up among the unvaccinated and extend its booster shot campaign.

The moves have encountered pushback by some Republican lawmakers, who argue that they are unnecessary because of "natural immunity" among the 45 million or more people in the US who have had confirmed COVID-19 diagnoses, according to a Washington Post report.

"The best way to stop COVID-19, including the emergence of variants, is with widespread COVID-19 vaccination and with disease prevention actions such as mask wearing, washing hands often, physical distancing, and staying home when sick," said Walensky of the latest data.

Five million death threshold breached

The finding was revealed as the world passed a sobering milestone in the pandemic, with data from Johns Hopkins University estimating that COVID-19 has now claimed more than 5 million lives worldwide – and that is likely to be an underestimate.

There have been 250 million cases of COVID-19 since the start of the pandemic, and while vaccines have curbed fatalities there is concern about a rise in cases in many areas of the world – including in some European countries like Bulgaria and Romania – that have lower vaccination rates.

Last week, World Health Organization (WHO) Tedros Adhanom Ghebreyesus highlighted once again the disparity between wealthy and poorer nations, noting that while more than 7 billion doses of vaccine have been administered worldwide, less than 4% of people in low-income countries have received a shot.

If vaccines had been distributed equitably, the WHO target of 40% vaccination in every country would have already been reached, he added.