Breakout Covid-19 infections will occur, but vaccination to determine lethality

Even highly vaccinated countries such as Israel, the United States (US) and the United Kingdom (UK), are all currently seeing huge surge of infections in recent weeks. “It’s a totally different ballgame with this Delta phase,” wrote Dr Eric Topol, a professor of molecular medicine at the Scripps Research Translational Institute in California.

In a way, Delta has decisively answered the question of whether vaccines will eradicate future Covid waves — they won’t. But vaccines will save lives.

The vaccine-death matrix

In the UK, 71% of overall population has been covered with vaccines and nearly 65% is fully vaccinated. In the past week, as the Delta wave continues to gather a foothold, the country has reported reporting 522 cases per million residents – one of the highest in the world among large population countries in the past week, according to data collected by Our World In Data.

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But what has been different from previous waves are the low death figures — only 1.98 deaths have been reported per million residents in the past week. This means that in the past week, 0.4% of cases have resulted in deaths. In contrast, the previous wave deaths in the UK were far worse – for the week ending January 23, the mortality rate was 3.3%.

Similarly, countries such as Israel (69% received shots, 63% fully vaccinated) has seen 888 new cases per million and 2.9 deaths per million in the past week — a mortality rate of 0.3%. For the week ending January 23, the morality rate was 0.8% in Israel.

To be sure, when calculating recent mortality rates, it is always better to account for a two-week lag as cases generally take 14 days to recover or (if things go south) end up in deaths. In other words, people getting infected today will statistically recover in around two weeks, or die. But recent numbers do give us a rough estimate of the human toll of an ongoing outbreak.

If we move this analysis to a country with a smaller proportion of vaccinated, then the results are completely different. In Thailand, for instance, 38% of the country has received a shot of the vaccine, with 16.6% full vaccinated. In the past week, the country has reported 3.15 deaths per million with 207 new cases per million. This translates to a mortality rate of around 1.5% in the past week – which means you’re four times more likely to die in Thailand than if you were a resident of the UK.

These numbers aren’t one-off comparisons and hold even when we group nations together. Across Asia, for instance, 47% of the population have been administered a single shot of the vaccine, with 32% fully vaccinated. The corresponding numbers in nations from the European Union are 66% and 60%. When we look at the mortality rate difference (in the past week), again the low vaccinated Asian nations have seen 1.6% deaths against 0.9% in EU countries.

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This makes it evident that breakthrough infections, though occurring far more frequently in Delta waves nearly throughout the world, can be countered – at least to prevent deaths.

The importance of the second dose

What can India learn from this phase of the global outbreak? The primary lesson is quite clear – good vaccination coverage will save lives.

India is trying hard to fix its patchy record. On average, in the past week, a little over eight million doses have been administered in the country every single day. While the record weekly pace was slightly high (around 8.4 million in the final week of August), the current pace is a massive improvement from the numbers we have seen throughout the drive. At its lowest, since the drive was thrown open to all adults, these numbers had dropped to under two million doses a day through May.

But a crucial sub-aspect of vaccination that needs attention for countering Delta waves is second dose coverage.

According to Our World in Data, India’s overall coverage of population by at least one dose is 40% — placing it marginally behind the global average of 42%. But it is India’s share of population fully vaccinated that continues to lag heavily – only 13% have received both doses, compared to a global average of 30%.

Even countries such as Russia and Indonesia, both behind India in total coverage (31% and 26% respectively), are ahead in their share of fully vaccinated – 27% and 15%.

To grasp the importance of the second vaccine, one must understand how multiple-dose vaccines work. Simply put, the first dose of a vaccine behaves like a primer for the body – it initiates contact with the immune system, telling it what to look for if an actual infection happens. This is also why the first dose has a higher chance of giving a more robust side-effect, compared to second dose (or booster shot). Once the immune system is primed, it is challenged again with a second dose which puts the knowledge from the first jab into practice, creating a larger immune response. This explains why countries such as the US and UK are already considering a third booster shot (which will create an even better immune response, according to scientists).

Nations the world over have shown that Delta variant can somewhat overrule advantages previously assumed to be gained from vaccination coverage. But the real gains of vaccination (though slightly reduced with the Delta variant) remain uncompromised – jabs (preferably two, or more) are likely to save you from the worse outcomes of Covid-19.

Numbers Matter examines Covid-19 trends, in India and globally, through the prism of data. The column is out every Tuesday.