Brazil’s Covid-19 vaccination program is being put at risk by people failing to show up for their second shot, with 1.5 million people missing appointments for the follow-up dose needed to maximize protection, according to the Health Ministry.
Specialists say that is particularly concerning after a recent real-world study from Chile found that the Sinovac Biotech (SVA.O) Covid-19 vaccine, which has accounted for some 80% of Brazil's program, is just 16% effective after one shot.
“Without the two doses, we get neither full protection nor a long duration of protection,” Juarez Cunha, head of the Brazilian Society of Immunizations, told Reuters. “We need people to do the full cycle.”
Until this week, more people were dying in Brazil of Covid-19 than anywhere in the world, with President Jair Bolsonaro widely criticized for opposing lockdown measures and pushing remedies like hydroxychloroquine that provide little or no benefit. India has now surpassed Brazil in daily deaths.
In total, Covid-19 has taken more than 380,000 lives in Brazil, the world’s second highest death toll behind the United States.
The country’s vaccination program has also repeatedly missed targets due to a shortage of doses resulting from delivery delays of active ingredients from China and India.
Now, the failure of people to turn up for their second dose is an extra worry.
Specialists and authorities involved in the campaign said the low turnout appeared to be due to poor communication, with people either not realizing the importance of the second shot or simply forgetting when they were meant to go.
In some cases, they said, people might also have been put off by a strong reaction to the first dose, which can frequently cause short-lived fever and body aches. There have also been long lines at some vaccine sites, which can be offputting for priority groups vulnerable to Covid-19.
In response to a request for comment, the Health Ministry said it is preparing a national media campaign to raise awareness of the importance of getting the second shot. It did not comment on why so many people are not showing up to complete their vaccination cycle.
The ministry has previously said the problems are not due to a shortage of shots, with second doses held back to ensure availability on schedule.
But with so many second doses left over and with the promise of future deliveries, the ministry changed its guidelines last month to allow for all shots to be rolled out as first doses.
That stands in stark contrast with Chile, where the vaccination strategy has shifted to prioritizing second doses over getting more people an initial shot.
South America’s largest economy has a proud history of successful vaccination campaigns and polls have shown that the vast majority of Brazilians are keen to get inoculated. But scientists fear the message about second shots is not getting across.
“People need to wake up and hear every day on the radio, on television, that you have to get your second dose, that you can’t miss it,” said Cristina Bonorino, a member of the scientific committee of the Brazilian Society of Immunology.
The study in Chile, which analyzed vaccine effectiveness among 10.5 million people, found that efficacy in protecting against symptomatic illness rose to 67% from 16% with the second Sinovac shot. The AstraZeneca (AZN.L) vaccine, which makes up the rest of Brazil’s inoculations, by contrast is 76% effective two weeks after the first shot. read more
“If a person doesn’t get their second dose, there’s no guarantee at all that the immunization will work,” Bonorino said.