After more than a year of fear that someone in her multigenerational household would bring the coronavirus home and expose elderly grandparents to a potentially deadly disease, Vanessa Bain was breathing much easier by the end of March.
Almost everyone in their Menlo Park home had at least one dose of vaccine. And then her husband is positive. Within days, so did her grandparents, as well as Bain and her teenage daughter, who were too young to be vaccinated.
Their story is a warning story and a celebration of vaccines. Yes, one or more members of the household can be so-called breakthrough cases – people who become ill after being fully vaccinated. But her grandparents, 81 and 95 years old, and who are considered a very high risk for serious illness and death due to COVID-19, are doing well, although they have tested positive.
‘Both appear to show relatively mild symptoms. I think it means that the vaccine was effective in preventing them from ending up in hospital, which is fantastic, “said Bain, 35, who is still not feeling well about two weeks after testing positive for herself. ‘I’m really glad they got the vaccine, even though they got COVID. I think things would be really different if it were not. ”
Nearly 30% of Californians 16 years and older – those so far approved for the vaccines – have now been fully vaccinated, according to state data. As these numbers continue to climb, public health officials are increasingly interested in breakthrough cases, which are defined as people who test positive and have symptoms of COVID-19 after being fully vaccinated.
These cases should be rare – and are fully anticipated. The vaccines are not 100% effective, and because the virus is still fairly widespread in California, there are likely to be some cases in people who have been fully vaccinated. California does not yet report breakthrough cases in public, but a survey among Bay Area counties found that more than 100 have been confirmed or suspected.
The breakthrough cases are important to detect as they can provide useful clues as to how the vaccines work and how the virus changes. Breakthrough cases will help experts in the infectious diseases to identify new variants that can evade vaccination. This will help public health officials understand how long the vaccine immunity lasts and whether, or when, they should start giving boosters.
There is pressure on public health authorities to create a national or state database of breakthrough cases. Such cases are likely to occur in a low number that data at the provincial level may not reveal important trends, such as the demographics of who becomes infected or which strains of the virus break through.
“Right now, a lot of people are collecting cases individually in different regions, but we all need them and as quickly as possible,” said Stacia Wyman, senior genomics scientist at the Innovative Genomics Institute at UC Berkeley, where her team tracks breakthrough cases. . ‘This is an issue that needs to be studied en masse, and every possible sample collected. It had to be arranged yesterday. ”
Ironically, breakthrough cases will give the assurance that the vaccines work as advertised, as is the case with Bain’s family. Although at least seven members of the family eventually tested positive for the virus, three of them were only partially vaccinated and one was not vaccinated at all. Most important to Bain: the vaccines protected the most vulnerable people in her home from serious illnesses.
Studies have found that the two main vaccines, from Pfizer and Moderna, were more than 90% effective in preventing mild to moderate cases of COVID-19, but essentially 100% in preventing hospitalization and death. The Johnson & Johnson vaccine is approximately 75% effective in preventing moderate illness and is also close to 100% in preventing hospitalization and death.
The hospitalization and death data are the key to the reopening of California and the bygone days of the pandemic. If people who are vaccinated rarely or never end up in the hospital or die, the state’s response to public health does not have to be as aggressive.
One of the most important measures for the planned reopening of California on June 15 is keeping hospitalizations low, especially among those who have been vaccinated. Government officials did not say when and if they would make the information available to the public.
The vaccines seem to be doing exceptionally well so far, public health experts have said. Among the suspected breakthrough cases identified by provinces are many people who have no symptoms but tested positive during routine examinations or because they had a known exposure to someone with COVID-19.
There are only a handful of reports of people being hospitalized with COVID-19 after being fully vaccinated.
‘We have now given more than a million and a half doses in Northern California. “Of the people who were fully vaccinated, we saw that a total of one case was admitted to hospital,” said Dr. Stephen Parodi, co-executive director of the Permanent Medical Group at Kaiser Permanente, said. “It’s encouraging.”
Sonoma County has identified about 30 suspected or confirmed breakthrough cases, and San Mateo County about 40. Marin County had six, Drs. Matt Willis, the health officer, said.
“I suspect it’s a countdown,” he said. “What is important is that these cases are milder, that they are shorter in duration and less severe.”
The California Department of Public Health has provided provincial criteria for detecting and investigating suspected breakthrough cases, and said the cases would be given preference for genomic sequencing to determine if worrying variants are the source of infection.
Studies have found that two variants first identified in South Africa and Brazil – both found in the Bay Area – are slightly resistant to vaccines. Infectious disease experts say the vaccines still need strong protection, but they want more information to support the assumption.
And these are not the only variants that can cause problems. The coronavirus mutates frequently and is more likely to develop mutations that help evade vaccinations as more people are vaccinated.
Wyman is about to launch a study with Kaiser to use genomic sequencing to look for mutations that could help the virus infect people who have been fully vaccinated, she said. She is trying to start another study at UC Berkeley that will do genetic testing on every positive test result that comes through campus labs, and in the same way is trying to identify new variants.
The hunt for variants is just one reason to study breakthrough cases. As more cases are recorded, doctors can identify trends that can help them figure out who has the greatest risk of having diseases after being vaccinated. They will be particularly interested in cases that appear in the first groups of people to be vaccinated, which will be the ‘vanguard’ of declining immunity – the first to become ill as the vaccine’s protection disappears, Willis said.
And hopefully everyone feels more at ease that the vaccines hold, and it’s safe to start over and resume pre-pandemic life.
“It is important to realize that we do not expect perfection, but that we prevent a lot of illness and death,” said Dr. Catherine Blish, an expert in infectious diseases at Stanford, said. “The vaccines are performing even better than we would have expected.”
Erin Allday is a staff writer for the San Francisco Chronicle. Email: [email protected] Twitter: @erinallday