Amid rising worries over the Delta variant, a comprehensive new analysis from the US brings a welcome dose of excellent news for those who are fully vaccinated against Covid-19.

The SARS-CoV-2 pandemic is the most widely and closely studied disease outbreak in human history. Moreover, we are living in an era of medical technology, data sharing, near-instantaneous global communication, and sheer raw computing power that would have been unimaginable during the last global pandemic, just over 100 years ago. Accordingly, an immense array of data is getting crunched every day, in every way, and naturally with all that analysis comes fresh new information on a regular basis.

Now, at last, there appears to be some really good news.

A just-released deep-dive analysis has found that breakthrough Covid-19 infections among the fully vaccinated are almost as tantalisingly rare as hospitalisations and deaths from the virus.

That upends what was previously thought, namely that while severe illness and deaths were exceedingly rare among the fully vaccinated, breakthrough infections still occurred at a higher rate.

Well, they do, but only marginally higher.

According to data analysed in the United States, less than 1% of fully vaccinated people experienced a breakthrough infection. The results were found through a Kaiser Family Foundation analysis of official state data. (KFF is a leading health policy analysis non-profit organisation in the US.)

In the US, the federal government only reports data on breakthrough infections that result in hospitalisation or death. This analysis from KFF, however, looked at data from individual states, giving it a much clearer and more complete picture.

According to the latest federal data from the US Centers for Disease Control and Prevention, less than 0.004% of people who have been fully vaccinated against Covid-19 experienced a breakthrough case resulting in hospitalisation, and less than 0.001% have died from the disease. By the raw numbers, that’s about 6,600 severe breakthrough cases out of more than 163 million fully vaccinated people.

But by looking at state-by-state data rather than just federal data, the KFF analysis shows that breakthrough infections of any kind are also incredibly rare.

About half of America’s 50 states report specific data on Covid-19 breakthrough cases, and in each of those states, less than 1% of fully vaccinated people had a breakthrough infection, ranging from 0.01% in Connecticut to 0.9% in Oklahoma. (The overall vaccination rate is higher in Connecticut, which may be part of the general pattern of fewer breakthrough cases when more of a population is immunised.)

Additionally, more than 90% of all cases – and more than 95% of hospitalisations and deaths – have been among unvaccinated people, according to the KFF analysis. In fact, in a majority of states, more than 98% of cases were among the unvaccinated. 

A caveat that’s worth noting here for those of us in Malaysia: The take-up of vaccinations is far higher in the US at this point, with 70% of all eligible residents there having received at least one dose of an authorised vaccine. (The first dose rate is currently about 43% in Malaysia.) Additionally, the vaccines being utilised in America are different from those offered here, with Pfizer-BioNTech’s mRNA vaccine the only common one currently in use. In the US, the other two primary vaccines authorised for use are Moderna (also mRNA), and Janssen (also known as Johnson & Johnson).

In Malaysia, six vaccines have been authorised for use: Pfizer, Oxford-AstraZeneca, Sinovac, Sinopharm, CanSino, and Janssen. Currently, the first three vaccines are in widespread use here. Malaysia has also announced it will no longer use the Sinovac vaccine in the National Immunisation Programme once its stocks are depleted, switching instead to Pfizer.

Fortunately, the one vaccine common to the US and Malaysia – Pfizer – forms a very large part of Malaysia’s vaccine arsenal (45.7 million doses secured to date), so in theory, that should help bring the two countries’ data sets closer together than they might otherwise be. While we may not see the exact same rates of protection and breakthrough cases, the latest data from the US is nevertheless extremely encouraging and underscores yet again the incredible effectiveness of these vaccines.

Stay safe. Stay strong. Get vaccinated. Take care of each other.