Almost everyone in Iran has been infected with the coronavirus at some point during the COVID-19 pandemic, and some have caught the virus more than once, but the country still has not achieved herd immunity, the New scientist To reported.
Instead of collective immunity, the trade publication said, Iran was witnessing a new wave of punitive deaths driven by the delta variant of the coronavirus.
The country of 84 million has seen about a month of relatively lower COVID-19 numbers, but the virus now appears to be on the rise again for a sixth wave. As of October 20, daily infections were again crossing the threshold of 10,000. The official coronavirus death toll, meanwhile, stands at 124,000, although officials have admitted the actual number could be twice as high. At the height of Wave 5, daily deaths were well over 500.
Iranian Health Minister Bahram Eynollahi said last week that Iran must achieve an 80% coronavirus vaccination rate. But figures from his ministry showed that only 35% of Iranians were fully vaccinated with two shots of the vaccine, with 75% of individuals registered as “one shot”. The published figures appeared to be percentages of adults over a certain age, but the data was unclear.
The vaccinations would stop the many hospitalizations but COVID-19 would not disappear completely, added the minister.
The evidence is piling up
New scientist refers to how the evidence is mounting that the immunity conferred by coronavirus infection wanes. An Indian study found a 27% COVID-19 reinfection rate during an outbreak in the country caused by the delta variant earlier this year.
Mahan Ghafari of the University of Oxford was quoted by the newspaper as explaining how, to address the lack of information on coronaviruses at the provincial level in Iran, he and his colleagues analyzed figures from the Iranian National Organization for civil registration (NOCR) which recorded the number of deaths there were from all causes during the first nine months of 2020. After comparing them with historical data to see how many there were more deaths than usual, the researchers used the excess deaths figure as a proxy to estimate the number of deaths from COVID-19 and exposure to the virus at the population level.
The researchers were reportedly able to piece together the dynamics of the pandemic in Iran from January 2020 to September 2021. After calculating how many people in each province had contracted COVID-19 using known global figures on the percentage of people infected who die, known as the Infection Death Rate (IFR) – for each age group and dividing the number of excess deaths by the IFR, they produced an estimate of the number of infections and a “Viral attack rate”.
Infected “twice and thrice”
New scientist concluded: “The analysis showed that the total infected population was probably very high in many provinces. Eleven of them had rates above 100 percent as of September 17. The highest rates were seen in Sistan and Baluchestan province, which had an estimated attack rate of 259%. If this is correct, it would mean that most people have had the virus twice and some a third time. The researchers conclude that herd immunity through natural infection was not achieved in Iran despite widespread exposure to the SARS-CoV-2 virus, possibly due to the decrease in immunity over time, sensitivity to new worrisome variants like the delta or a combination of both. “
Marc loeb at McMaster University in Canada said studies using direct measures of infections were needed to conclusively determine the attack rate of the virus for a given population, but found the study’s conclusions plausible . “Overall, what’s happening on a global scale is that it certainly seems like antibodies are dropping and there isn’t that point where, miraculously, herd immunity or the collective effect is achieved, “he said.
Loeb added, however, that he was not aware of any pathogens for which herd immunity has been achieved without vaccination. “By far the safest and most effective way to obtain herd immunity is through vaccination,” he determined.