It’s truly spectacular that one year after the start of the pandemic, we have not one but multiple working vaccines. It’s much better than even the optimistic forecasts, and vaccine rollout is already in full swing in several countries. But we’re not out of the woods yet. In addition to the expected logistical problems of producing and distributing vaccines, there’s the problem of vaccine hesitancy, and the long-term issue of virus variants.

Reports of coronavirus variants such as the ones coming from South Africa, Brazil, and the UK have stoked fears not just of a more contagious or dangerous virus, but that one such variant (or several) could render vaccines ineffective. Here, we’ll look at just some of the most concerning variants that have emerged so far and what we know about vaccine efficacy on them, but it’s important to know that the more the virus spreads, the more the risk of new variants increases.

The Brazilian variant (P.1)

The Brazil variant emerged in July and features a mutation called E484K, which may help it evade some parts of the immune system. The variant emerged as particularly concerning since it caused widespread infection in the city of Manaus, even as the city had already experienced a widespread infection. Immunity from the original virus seemed to not provide sufficient protection from the new variant.

The variant does not appear to be more deadly, but it does spread more easily than the original one. The variant has already spread to multiple countries outside of Brazil, with multiple cases being confirmed not just in South America, but also in Italy, Germany, and Belgium, raising concerns that the variant is already widespread.

Do vaccines work on the Brazilian variant?

There is not much information regarding vaccine effectiveness on this strain. A very recent study (which has not yet been peer-reviewed) suggests that the Pfizer and AstraZeneca jabs could offer substantial protection against this variant. Professor Gavin Screaton, head of the medical sciences division at Oxford, who led the research, told Reuters:

“The results suggest that P1 [the Brazil variant] might be less resistant to vaccine and convalescent immune responses than B1351 [the South African variant], and similar to B117 [the Kent variant].”

The results are encouraging, though far from clear, and still need to be reviewed by external experts. The researchers also note that, to a lesser extent, natural antibodies also offer some protection. Johnson & Johnson’s single-jab vaccine was also encouraging: it was 66% effective in the initial trials in Brazil, where the variant was already dominant.

The bottom line: some of the existing vaccines seem to offer some protection, though it’s hard to say exactly how much and how long-lasting it is. More research is required.

The British variant (B.1.1.7)

The British (or Kent) variant emerged in September 2020 and caused a stir straight from the beginning. It seems to be much more contagious than the original version (estimates ranging from 30% to 70% more contagious), and it also seems to cause more severe cases and hospitalization.

The British variant is already widespread and has become the dominant variant in multiple countries.

Do vaccines work on the British variant?

The good news is that although it is more dangerous and more contagious, the variant is neutralized by existing vaccines.

• The Pfzer vaccine: early results suggest that the Pfizer vaccine seems to offer protection against the British variant. Researchers have expressed “cautious optimism.”

“We think our vaccine is robustly active against all strains,” Pfizer Chief Scientific Officer Mikael Dolsten said in an interview Feb. 25. Being an mRNA vaccine, it is also customizable with relative ease.

• The Moderna vaccine: according to unpublished data, the Moderna vaccine seems to offer similar protection against the British variant, and Moderna is reportedly working on modified vaccines that offer increased protection against the variant.

Much like the Pfizer vaccine, Moderna’s is also easily customizable, which is also encouraging.

• The AstraZeneca vaccine: according to a peer-reviewed study, the AstraZeneca vaccine offers full protection against the British variant — there seems to be no difference for this particular variant in the AstraZeneca vaccine.

The Johnson and Johnson vaccine also seems to offer protection against this variant, and according to company officials, Johnson and Johnson is excellently positioned to adapt its vaccine.

“We’re quite confident based upon the clinical data that we already have with our vaccine that we’re going to see a very robust response, but we’re simultaneously doing the exact same thing [as other companies working on variants],” Johnson & Johnson CEO Alex Gorsky said.

The South African variant (B.1.351)

The South African variant is perhaps the most concerning one vaccine-wise. It shares some similar mutations with the Brazilian mutation, which affect the virus’ spike protein. However, this variant triggered a much larger reduction in virus neutralization.

The variant has already spread internationally, with over 100 cases being detected in the UK, Israel, Austria, and the Netherlands — though the real incidence is probably much higher. The variant is not believed to be more dangerous, but it is more contagious than the original virus, possibly comparable to the UK variant.

Do vaccines work on the South African variant?

• The AstraZeneca vaccine: The vaccine shows a 9-fold reduction in efficiency compared to the original virus.

South Africa stopped vaccinations with the AstraZeneca vaccine after the vaccine was found to be ineffective. Overall vaccine efficacy against mild-to-moderate COVID-19 for the variant was found to be 10.4%. However, the jury is still out on whether the vaccine can protect against severe cases and make them milder.

• The Pfizer vaccine: The vaccine efficacy is reduced by two thirds.

Here too, the vaccine may protect against the severe forms of the disease, but the virus seems to be able to evade vaccine in a concerningly large percentage of cases.

• The Moderna vaccine: The vaccine efficacy is also believed to be reduced against this variant, though data is lacking in this regard. The company is already trying a third or a booster shot specially tailored against the variant.

• The Novavax vaccine (which will get FDA approval by May and maybe even a bit sooner in Europe) is less than 50% effective against the South African strain.

What about the other variants?

These are the three most notable coronavirus variants, but there are other potentially significant variants as well.

At this moment, these appear to be the most widespread and data is very limited on other variants (even on these three, data is still lacking). The more the virus is allowed to spread, the more the risk of dangerous variants increases. As the situation continues to develop and unfold, vaccine developers are keeping an eye out and working on ways to improve vaccine efficacy for different variants.

The bottom line

Vaccines are our way out of the pandemic — there’s simply no way around it, all the other roads lead to catastrophe.

So far, vaccine efficacy seems to be satisfactory in all variants but the South African one. It’s unclear how well the existing vaccines prevent severe cases, but when it comes to overall efficacy, all vaccines seem to offer less than 50% protection with this variant. While still far better than nothing, this is not exactly a best-case scenario.

The worst-case scenario would be if the South African variant (or another variant capable of evading vaccine protection) becomes the dominant one. There is no reason to believe this variant is more contagious than the British or the Brazilian one, for instance, but it can still become dangerously widespread.

For now, it’s an arms race: the virus will continue to adapt and change, while researchers will continue to target it with new vaccines. We, the individuals, can also help in this arms race, by doing our best to reduce viral transmission as much as possible and getting vaccinated as quickly as possible.